The tensile stress of rubber bearings is critical for the design of isolated structures. To study the force state of isolation bearings after the occurrence of tensile stresses， a hypothesis of bearing lift-off behavior is proposed， and the lift-off state is summarized as a force-balanced bearing reduction system， thus obtaining a straightforward solution for the lift-off state. The concept of load equivalent eccentricity， which is suitable for measuring overturning effect， is proposed by analogy with eccentric compression members， and a conversion coefficient is adopted to express load combinations uniformly， so as to obtain a more concise expression. The analytical formulas of equivalent eccentricity， internal force and stress of bearing and overall rotation angle at each stress stage were derived. The critical average compressive stress of bearing was proposed， and the corresponding height-width ratio limits were calculated. The results show that the tensile stress of the bearing is mainly affected by horizontal earthquake action， height-width ratio， bearing performance and arrangement； in the area of 8 degrees （0.2g）， 8 degrees （0.3g）， 9 degrees （0.4g）， the limit of the equivalent eccentricity when the bearing is allowed to have tensile stress is 0.24， 0.22， 0.2， respectively， and the height-width ratio limits is 4.5， 3.5， 2.5， respectively.