Based on daily data of micro-climate observation and automatic meteorological observation station at Linzi, Laiwu, and Lijin from 2011 to 2015 (from November to next May), the SEM (structural equation modeling) and AHP (analytic hierarchy process) are used to choose factors of causing tomato's low temperature stress by continuous shading in solar greenhouse and the forewarning model is built. The daily data of micro-climate observation and automatic meteorological observation station at Linzi, Laiwu，Lijin， Pingdu, and Zhangqiu of Shandong from 1 November 2016 to 31 May 2017 and Jinghai of Tianjin and Xushui of Hebei from 1 November 2015 to 31 May 2016 is utilized to test the forewarning model. The results are listed as below. 1) Factors of causing low temperature stress by continuous shading under three days (between one and three days) are minimum indoor air temperature one day ago, minimum outdoor air temperature one day ago, minimum indoor ground temperature at 20 cm one day ago, minimum outdoor air temperature on that day, and sunshine duration one day ago; while factors of causing low temperature stress by continuous shading over three days (between 4 and 12 days) are minimum indoor air temperature two days ago, minimum indoor air temperature one day ago, minimum outdoor air temperature one day ago, and minimum outdoor air temperature two days ago. 2) The data of low temperature stress by continuous shading in solar greenhouse under or over three days during main production season in Linzi, Laiwu, Lijin, Pingdu, and Zhangqiu of Shandong, Jinghai of Tianjin, and Xushui of Hebei is used to verify the forewarning results of the model. The average accuracy of forewarning grades in full accord with actual grades is 72% and 74%, respectively; the deviation within one grade is 99% and 98%, respectively.