Testing to the problem of extreme high temperature for Xichang onion seed production in summer, the top of the shade is established, in the 0～100% within the range of the control facilities shed luminous flux, the temperature is controlled by shading. The different part temperature of the facility shed and the temperature variation outside facilities shed showed that in the summer high temperature timing with sunshade net in the range of 0%～ 100% coverage of controlling light, the cooling effect is obvious, which can significantly change the local environment of the facilities shed and is favorable for onion seeds flowering and fruiting