We design and analyze a kind of oblique-cone-slid-ring (OCSR) assembly seal device used in carbide actor that can self-compensate the seal wear. The effect of the OCSR thickness variation on the contact stress, Von mises stress, and spring force is analyzed using ANSYS software. It shows that the OCSR assembly seal device can seal well and has the function of self-compensation to seal wear when the OCSR thickness vary during the experiment conditions given. The max contact stress on the seal surface and other contact face is higher or much higher than the work stress of sealed medium. That means the design is satisfied with the user demand. The results provide a theoretical base for the further study and applications of the OCSR assembly seal device.