The extent of seasonally frozen soil is shrinking under global warming. The influence of seasonally frozen soil on springrunoff, especially on the spring peak flow is making the concerned study necessary. In order to analyze the influence and controllingfactors of seasonally frozen soil in the mountain areas with different elevation, this study used the path analysis method to analyzethe influence and controlling factors of the maximum depth of frost penetration and thawing days in the Kaidu River basin.The results indicate that the influencing factors of the maximum depth of frost penetration and thawing days are similar under differentelevation, while the controlling factors are different. The controlling factors of the maximum depth of frost penetration changefrom the negative accumulative temperature and maximum snow depth in lower elevation to average relative moisture in middle andhigh elevation. The controlling factor of the thawing days change from the average wind speed and maximum frozen depth in lowerelevation to average relative moisture in high elevation. The difference is primarily determined by the geophysical condition and localclimate condition in different elevations.