Abstract: The major unstable modes of gravity retaining walls are overturning and sliding.In order to compute the failure probability of structural systems for stability of gravity retaining walls,firstly,two performance functions against overturning and sliding of gravity retaining walls were established.Then,the first order second moment theory in structural reliability analysis,i.e.,the checking point method(JC method) was introduced to compute the two failure modes respectively,and two corresponding reliability indexes could be obtained.It was assume that the two failure modes formed a serial system and the reliability index of structural systems could be computed by the equivalent plane method.Finally,the failure probability of structural systems for stability of the retaining walls could be computed by the reliability index of structural systems.Taking a practical gravity retaining wall for an example,the reliability index and failure probability of structural systems were computed by MATLAB program.