The main maize variety ‘Zhenghong 505’ in the central hilly area of Sichuan Province was selected as experimental material in 2016, 2019, and 2020. Five sowing dates were set to study the differences of meteorological factors under different sowing dates and their effects on the maize growth process and yield, to build the theoretical basis and establish guideline for maize sowing date optimization in this area. The results showed that the daily average temperature increased, the vegetative growth period of maize shortened, and the active accumulated temperature decreased. Meteorological factors mainly affected the vegetative growth stage of maize in the whole growth period. Correlation and regression analysis showed that temperature is the main meteorological factor determining the growth process of maize. The contribution rate of daily average temperature and active accumulated temperature to each growth period was 83.0%, of which 99.9% was from silking to maturity. The grain yield was affected by temperature, light, and precipitation at the same time. The contribution of light conditions was larger (35.7%-54.0%), the contribution of daily average mild active accumulated temperature was 25.2%-31.2%, and the contribution of rainfall was 20.8%-33.1%. The contribution rate of meteorological factors to yield components were different. The contribution rate of meteorological factors to yield components were different. The temperature from sowing to silking contributed most to the number of grains per ear, and the light from silking to maturity contributed most to the 1000-kernel weight. With the delay of the sowing date, the biomass and grain yield increased first and then decreased. The regression equation between grain yield (y) and sowing date (days after the first sowing date, x) was y=–1.16x2+19.87x+7977.34, R2=0.47**, the highest on April 3. Therefore, early April was the suitable sowing date for a high yield of maize in this region according to this study.