Abstract: International crop models developed based on European and American spring oilseed rape varieties exhibit limited adaptability when applied to winter oilseed rape in China, primarily due to their inability to capture the nonlinear temperature responses associated with vernalization requirements. To improve the simulation accuracy of developmental stages, this study developed a nonlinear temperature-driven development model based on the Temperature-Accumulated day (TAd) algorithm of the Chinese AgroMeteorological Model (CAMM). An exponential temperature efficiency coefficient k_T\text=exp(-k\timesT_A) was introduced to quantify the nonlinear temperature response, and the improved model was termed eTAd (exponential TAd). The model was calibrated and validated using phenological and meteorological data from 85 agro-meteorological stations across 12 winter oilseed rape-producing provinces during 2000–2024. A grid search method was employed to optimize the temperature efficiency parameter k for different developmental stages, with the optimal k values determined as 0.06 for the emergence-to-anthesis stage, 0 for the anthesis-to-maturity stage, and 0.04 for the sowing-to-emergence stage (where k=0 reduces the eTAd model to the original TAd model). Regional simulations were driven by the China Meteorological Administration Land Data Assimilation System (CLDAS) gridded meteorological data at 5 km resolution for the period 2008–2024. Parameter regionalization was implemented through an improved spatial interpolation method, LABdIDW, which incorporates latitude, altitude, and base distance as weighting factors, with the mean absolute error for the thermal threshold parameter for the emergence-to-anthesis stage ( T_Ad1 ) interpolation reduced by approximately 5.0% compared to the conventional inverse distance weighting (IDW) method. The performance of the eTAd model was evaluated using both back-substitution validation and independent-sample validation. The results from the two approaches were closely comparable across all growth stages; specifically, for the emergence-to-anthesis stage, the RMSE values were 8.89 d and 9.10 d, and the coefficients of determination (R²) were 0.64 and 0.60, respectively, indicating good extrapolation ability and no significant overfitting. Compared with the original TAd model (k=0), the eTAd model reduced the RMSE for the emergence-to-anthesis stage from 10.00 d to 8.89 d, corresponding to an 11.1% reduction. Validation across temperature zones showed that the improvement was most pronounced in the high-temperature zone, with an RMSE reduction of 16.77% (from 11.81 d to 9.83 d), followed by the moderate-temperature zone (10.46%), while the low-temperature zone exhibited only a minor change (0.89%). These findings suggest that the bias of the original model is primarily associated with high-temperature conditions. The thermal threshold parameter for the emergence-to-anthesis stage ( T_Ad1 ) exhibited a distinct “high in the south, low in the north” latitudinal pattern, reflecting the physiological mechanism that warmer southern regions require greater heat accumulation for anthesis due to incomplete vernalization. The thermal threshold parameter for the anthesis-to-maturity stage ( T_Ad2 ) showed high values in the Yunnan Plateau, the Sichuan Basin, and the middle and lower reaches of the Yangtze River, suggesting heat stress effects on grain filling. During 2008–2024, the anthesis date advanced significantly at a rate of 0.82 d/a ( P<0.01 ), equivalent to an accumulated advancement of approximately 14 days over the 17-year period. The maturity date exhibited significant advancement during 2015–2024 at a rate of 0.77 d/a ( P<0.05 ), while the emergence date showed no significant trend. Regional disparities were evident: significant advancements in anthesis were observed in Sichuan, Yunnan, and Henan provinces, while Jiangsu and Anhui showed no significant trends. The maturity date showed a north-south divergence, with Jiangsu exhibiting a significant delay and Hubei and Sichuan showing significant advancements. The emergence-to-maturity duration also shortened significantly at a rate of 0.30 d/a ( P=0.016 ). These phenological changes led to a restructured growth period, with the vegetative phase shortened most markedly. The eTAd model provides a parsimonious and reliable tool for simulating winter oilseed rape developmental stages, and the phenological patterns revealed by the model offer valuable insights for variety zoning, sowing date adjustment, and flowering-period tourism services under climate change.