Abstract: This study aims to explore the effects of radio frequency-assisted hot air drying (RF-HAD) on the drying characteristics and physicochemical properties of Litopenaeus vannamei (L. vannamei). Hot air drying (HAD) at 60 ℃ was taken as the control. A systematic investigation was also made to clarify the impacts on drying characteristics, water distribution, color, texture, astaxanthin content, antioxidant capacity, protein secondary structure, and microstructure under various drying temperatures (60, 70, and 80 ℃), and electrode gaps (107, 117, and 127 mm). The results showed that there was a dynamic variation in the internal temperature of L. vannamei during drying. The transverse relaxation time was adjusted to shorten the drying time by 47.22%-72.22%, compared with the HAD. The L. vannamei contained a high amount of the free water initially, and then evaporated, as the drying proceeded, leading to a great reduction in the free water content. At the last stage of drying, the bound water was the main component of the moisture in the L. vannamei, which was more difficult to remove. Therefore, the drying rate decreased, as the drying time increased. The T2b value was significantly reduced (P<0.05) under the RF-HAD treatment, compared with the HAD. The RF-HAD L. vannamei tissue shared a stronger binding to water. The moisture of each component was removed continuously. At the same time, the immobile water was converted into bound water during RF-HAD. Additionally, the drying rate increased with the decrease of the electrode gap at the same RF-HAD temperature. There was a large proportion of the peak area that was occupied by bound water. Specifically, 107 mm treatment was more conducive to improving the drying efficiency. Besides, the L* value increased by 17.39%-21.70%, compared with the HAD. The RF-HAD treatment has enhanced the brightness of L. vannamei. Specifically, the L. vannamei dried at 60 ℃ with an electrode gap of 117 mm shared a higher L* value (51.23) and lower ∆E value (7.64), in order to better preserve the color of L. vannamei. The cohesiveness and chewiness of the L. vannamei after RF-HAD treatment were reduced by 34.88%-74.48% and 35.75%-79.49%, respectively, compared with the HAD, indicating improved palatability. Furthermore, the higher content of astaxanthin was observed at the same temperature of the RF-HAD, when the electrode gap was 117 mm, compared with 107 or 127 mm. The content of astaxanthin in the RF-HAD treatment groups at 70 and 80 ℃ was lower than that at 60 ℃. Specifically, the L. vannamei dried at 60 ℃ with an electrode gap of 117 mm shared the highest astaxanthin content (20.70 μg/g), indicating the slow degradation of astaxanthin. The 1,1-diphenyl-2-picrylhydrazyl (DPPH) scavenging increased by 42.36% and 58.33%, respectively, at 60 ℃ with the electrode gap of 117 mm, compared with the 107 and 127 mm treatments, indicating the stronger antioxidant capacity and protein thermal stability. Scanning electron microscope (SEM) images revealed that the muscle fibers varied more outstandingly at the higher temperature and lower electrode gap. Moreover, the fractal dimension (1.923 0) at 60 ℃ with an electrode gap of 117 mm was quite lower, compared with the 107 and 127 mm treatments. The microstructure of the L. vannamei dried was relatively simple. Pearson’s correlation analysis showed that there was a correlation between the color and texture. Besides, the astaxanthin content was highly significantly positively correlated with the elasticity (P<0.01), although it was highly significantly negatively correlated with the hardness (P<0.01). Meanwhile, there was a significant positive correlation between DPPH scavenging and elasticity (P<0.05). This finding can provide the theoretical reference and technical assistance for the deep processing of the L. vannamei.