Abstract: A split-plot sowing experiment was conducted to expose the materials to three types of climatic conditions during the sensitive heading and flowering period: persistent high temperature and drought, dramatic fluctuations in temperature and humidity, and relatively favorable conditions. By monitoring temperatures and humidity within the canopy and analyzing indicators such as flowering habits, stigma exertion rate, and outcrossing seed rate, the effects of temperature and humidity on the outcrossing characteristics of CMS-D1 Xinye A during hybrid seed production were investigated. The results showed that under favorable conditions with an average daily temperature of 25.0~27.0 ℃, the flowering period of Xinye A lasted for 8 days, with the peak flowering period concentrated on the third day after heading. The forenoon flowering rate was extremely significantly positively correlated with temperature (0.824) and extremely significantly negatively correlated with humidity (-0.816). The flowering peak occurred at 11:30. Exposure to persistent high temperatures (daily mean temperature＞31.0 ℃), especially when combined with low humidity (daily minimum humidity＜50.0%) from the late stage of young panicle differentiation to the flowering period, severely reduced the stigma exertion rate and outcrossing seed rate of Xinye A. Therefore, in hybrid seed production of Xinye A, it is necessary to avoid high-temperature and drought stress, adjust the peak flowering period of the paternal parent to the third day after the maternal heading, and enhance supplemental pollination during the midday flowering peak (11:00~12:30) to improve outcrossing seed set.