Abstract: In order to improve the meteorological disaster prevention of winter pitaya（Hylocereus undatus ′Foo-Lon′） facility cultivation in Hubei province, the daily variation characteristics of the minimum temperature inside and outside the winter pitaya greenhouse by using the data of the small weather monitoring station in Yangxin county, Huangshi city, Hubei province. The diurnal variation characteristics of the minimum temperature inside and outside the greenhouse in winter were analyzed. Based on the single factor correlation analysis of the minimum temperature inside the greenhouse with the temperature outside the greenhouse that day and the temperature inside and outside the greenhouse that day, model factors were selected, and the prediction model of the minimum temperature inside and outside the greenhouse in winter was constructed and verified by the stepped-regression method. The results showed that, during the observation period, the minimum temperature inside the greenhouse was higher than that outside the greenhouse, and the lower the temperature outside the greenhouse was, the greater the temperature difference between inside and outside the greenhouse was. The daily variation of the minimum temperature was larger than that outside the greenhouse. The lowest value appearred around 7：00（morning） in different weather conditions, while the highest value appearred around 14：00（afternoon）. The average absolute error of the measured and simulated values of the three models under different weather conditions was 0.49~1.20 ℃, and the root mean square error was 0.69~1.30 ℃, which were all below 1.30 ℃, and the fitting effect of the models was better.

Key words: pitaya（Hylocereus undatus ′, Foo-Lon′, ）, facility cultivation, microclimate, low temperature forecast