The strength and sealing performance of ethyleneacrylic elastomer(AEM) sealant strip used in engine oilgas separator at different temperatures were studied. The finite element model between rubber sealant strip and matching shell was established by means of finite element analysis software ABAQUS.The von Mises stress,compressibility,contact stress and contact width of rubber sealant at different temperatures were calculated and analyzed by using Mooney-Rivlin model.The results show that the von Mises stress of the sealant strip and the contact stress between the sealant strip and the continuous contact surface of the shell are increased gradually with the increase of temperature,the contact width remains basically unchanged,and the compressibility of the sealant strip is decreased gradually.The von Mises stress of the sealant strip is far less than the tensile strength of the rubber material,and the strength requirement can be met.The contact stress on the continuous contact surface of the rubber strip is always greater than the working pressure of the oilgas separator and the contact width meets the requirements. The rubber strip meets the sealing conditions.