Abstract: Based on the statistical analysis of the frozen depth of the seasonal permafrost in Jilin, the authors obtained the formula h_o=a(√Ω+b) for calculating the frozen depth of the seasonal permafrost in the less snow years and in the no snow years, and the formula h=a (√Ω+b-kHx) for that where the annual mean depth of snow accumulation is over 2 cm under natural snow accumulation condition.The decrease in frozen depth of every cm of mean snow accumulation is s=a.k, and the frozen depth ratio of two adjacent measuring points is kh=aA/aB.The distribution of frozen depth of seasonal permafrost in Jilin has a positive state of distribution feature, taking the Peason’s Type Ⅲ curve cs-o as the theoretical frequency curve for the frozen depth of a designated place. Frozen depth of adjacent points appears in same frequency.Calculation of frozen depth applied in engineering design should base on the grade of engineering construction and the running conditions, adopting frozen depth hp of a certain frequency.