Research conclusions: The stability of the single pile composite foundation of high—speed railway in the hard—plastic silty clay could be determined by static test of the single pile composite foundation．During the test，the bearing plate was placed on the compacted soil of the composite foundation．The characteristic value of bearing capacity of the single pile composite foundation could meet the design requirements and its range Was not be more 30％than the average value．The settlement of the width of the bearing plate corresponding to the characteristic value of the bearing capacity of the single pile composite foundation bearing plate did not exceed S=0．004 d，and the settlement range of the characteristics value for bearing capacity of the single pile composite foundation did not exceed 30％of the average vahe．