The stability of the foundation is crucial for the production safety of jack-up platforms. Firstly， the checking methods of foundation stability in the international standard (ISO 19905-1 and SNAME 5-5A) for in-place analysis of the jack-up platform are introduced， and then an engineering example is introduced to check the foundation stability of the platform. The results indicate that the vertical horizontal bearing capacity and anti-sliding capacity of the foundation at the target operation site meet the requirements of both specifications. Due to the differences in the determination of vertical ultimate bearing capacity in both specifications， there are differences in the vertical-horizontal foundation capacity envelopes， and the verification results according to ISO 19905-1 are more conservative.