The failure case of sealing structure of slip hanger was studied,then finite element calculation of the hanging capacity and the working characteristics of the seal structure of the slip casing hanger was carried out.The main reasons for the frequent failure of the seal structure of the slip hanger were analyzed.In order to overcome the structural defects of slip hanger and improve the bearing capacity and sealing performance of wellhead hanger,a new type of mandrel hanger was designed and tested.The results show that the deformation of the hanger and the cross is within the safe range;the deformation of the spherical sealing ring is flat after being pressed,and the sealing width is large,which indicates that the sealing performance is good;during the pressure test,with the increase of the load,the displacements of the test-bed instrument and the dial indicator change little.Therefore,the pressure test shows that the new hanger can withstand the high pressure of 140 MPa.Finally it is applied in the field with good effect.