Abstract: Taking two kinds of shed structures of 12 meters and 30 meters as the test materials, the temperature and light intensity data of 5 kinds of greenhouses and open field controls in June of 2017 were studied and the agronomic characteristics and yield of bitter gourd under six cultivation methods were analysed by three ventilation cooling methods of side ventilation, surrounding ventilation, and top ventilation, in order to study the shed length of the rain shelter and the summer cooling effect under different ventilation modes.The results showed that there was no significant difference between the daily minimum temperature of each treatment and CK.The daily maximum temperature of the five treatments was significantly higher than that of CK;the daily maximum temperature difference between T1 and T2,T3 and T4 were not significant, and the average difference was within 0.5%,indicating that the length of the greenhouse has little effect on the cooling of the plastic greenhouse in summer; the analysis of the daily maximum temperature data showed that the higher the outside temperature, the worse and less obvious the cooling effect of the active cooling measures such as ventilation; the cooling effect of T5 is the most significant, lowering the temperature in the shed by 16.75%-44.69% compared with other treatments, that is, the ventilation method of ‘sides ventilation+top ventilation’,and the 30 m shed length has the best cooling effect in the greenhouse in summer and is beneficial to the growth and development of bitter gourd.