Abstract: The conical joint is a commonly used structure in engine line connections, and the sealing effect of conical joints with different size parameters varies. First of all, the physical model is established, and then the sealing characteristics of the tapered joint with 74° cone angle are studied by numerical calculation in order to obtain the optimal design parameters of the tapered joint cone angle. Finally, the response surface model and multi-objective genetic optimization algorithm are used to optimize the taper angle of the tapered sealing joint. The results show that the sealing effect is best when the conical joint angle of the positive end is 74.4°, and the cone angle of the negative end is 74.2°.