In order to improve the sealing performance of conical pipeline joint seals so as to meet the requirements of gas or liquid tightness performance,the main factors that determine the sealing performance of conical seal were explored by taking the plug as an example.The difference of sealing performance between plug and pipe joint seals was analyzed.The effects of the structural parameters on the sealing performance of conical pipeline joint seals were explored with the help of the finite element method,and the results were validated with the experiments.The results show that,during the assembly process,three obvious plastic zones are formed in the gasket of the conical sealing system,and the overall sealing performance is mainly affected by the contact stress and contact surface width of the three zones.The plug seal has better sealing performance than the pipeline joint seal.The local contact stress can be improved by reducing the chamfering radius and increasing he difference between the inner cone angles,while the overall sealing performance can be improved more effectively by reducing the contact area.