Based on the meteorological data, maize growth period and yield data of the main maize producing areas in Heilongjiang from 1981 to 2021, extreme wind speed and relative soil moisture are selected and their corresponding critical values suitable for maize harvest are constructed in different parts of the main maize producing areas in Heilongjiang by using the confidence interval estimation method. At the same time, this paper explores and analyzes the impact of precipitation and autumn temperature after the maize matures. The results are as follows. (1) The critical value of suitable daily extreme wind speed W0 is between 8.3 and 13.5 m[DK]·s^-1, the suitable relative soil moisture M0 between 71% and 94% at different stations in the study area, and the daily extreme wind speed equal to or smaller than W0 and the relative soil moisture equal to or smaller than M0 are suitable for maize harvest. The established indicators can better indicate the suitability of extreme wind speed and soil moisture for maize harvest in Heilongjiang. (2) During the main harvest period between the maturity of maize and 20 October, it is suitable for maize harvest in rainy weather with daily precipitation below 23.0 mm. (3) There is a significant correlation (P＜0.01 or P＜0.05) between the autumn average/maximum/minimum temperature and the grain weight of maize per plant, respectively. Within a certain temperature range, the grain weight of maize per plant shows an increasing trend as the autumn temperature rises, which indicates that higher autumn temperature has a positive effect on the maturity of maize.