Height of similar rockmass landslides in one tunnel section was processed with the statistical method in the existing design codes.However, the spatial variability within the similar rockmass length was not taken into account.In order to overcome the shortcomings, an equivalent deviation increasing function of the space rockmass landslides height σh(L) was put forward.And the WeibullБοлοгин statistical theory for brittle materials failure was employed to find the equivalent compressive strength of tunnel secondary lining with different concrete volumes.As a result, the problem of space structural system reliability for the deepburied tunnel could be simplified as a plane problem.Taking the class Ⅲ deepburied rockmass in Jinzhou tunnel as an example, the characteristic values of joint spacing, variance upper limit of rockmass landslides height and the length of the tunnel to affect the system reliability were analyzed.And it was shown that the system reliability index increased with the increase of characteristic values.The system reliability index decreased gradually with the increase of variance upper limit of rockmass landslides height and the length of the tunnel.However, the reliability index would be towards a stable value at the end.