Abstract: Based on the general formula for the stability analysis of common jointless tracks, the calculation method for the stability of switches of a jointless turnout is put forward. By taking the No.18 turnout in the Qinhuangdao-Shenyang passenger express line as an example, the relationship between the safety coefficient and the wave length, the original plastic camber and the allowable deformation camber is discussed, and a simplified formula for jointless turnouts completely welded is given. The results show that the frog heel of jointless turnouts is easy to lose stability, so the basic verification requirement for the stability of jointless turnouts is suggested as 2 mm for the original elastoplastic allowance camber and 1 mm for the allowable deformation camber.