Abstract: The temperature inside model greenhouses with the wall height of 1.26 m, 0.96 m, 0.66 m, 0.36 m was investigated, and some measures were adopted to reduce or exclude the effects of thermal storage of soil and air, in order to study the effects of wall height on night temperature in solar greenhouse. The results show that there is a significant effect of wall height on the night temperature of the greenhouse. The average temperature during night is increased as the wall height increasing. And the relative changing rate of night temperature indicates that the higher the wall, the lower the decreasing rate of night temperature of greenhouse. The night air temperature in the greenhouse with the wall height of 1.26 m is 1.2~1.8 ℃ higher than that with the wall height of 0.36 m. In addition, the average temperature of the greenhouses during night increases about 0.5 ℃ with increasing the ratio of wall surface area to total transparent surface area by 0.1, which suggests that increasing wall height reduces the speed of temperature decreasing and improves the property of heat preservation of the greenhouse.