Abstract: In order to study the influence of environmental factors in the solar greenhouse on the growth and development of facility tomato during the fruiting period, the quantitative relationship between environmental factors and the fruit growth and development of facility tomato was explored. Based on the autumn and winter tomato fruit growth data and environmental data in the Smart Agricultural Industrial Park, Mi Town, Lingcheng District, Dezhou City, Shandong Province, the correlation and multicollinearity between the data were analyzed, and the growth model of facility tomato in fruit stage was constructed by the method of stepwise regression and principal component regression. The results showed that there was a strong linear correlation between the fruit transverse diameter and the cumulative amount of various environmental factors, and the correlation coefficients between the fruit transverse diameter and the cumulative amount of various environmental factors（air temperature, air humidity, light intensity, CO₂ concentration, soil temperature） were 0.96, 0.95, 0.95, 0.94, 0.94, respectively. There was a strong multicollinearity among the environmental factors in the greenhouse, and three significant environmental factors were analyzed by stepwise regression, including air temperature, light intensity and CO₂ concentration. The determination coefficient of the facility tomato fruit growth model established by principal component regression was 0.93, and the fitting effect was good.