The kinds of diseases of the turnout zone are multifarious-By using a spatial coupling vehicle-turnout system model，the effect of diseases such as the incomplete closing of tongue rail，frog wear and interval iron losing efficacy to the wheel /rail system interaction is simulated. The results show that the incomplete closing of tongue rail will aggravate the vertical and horizontal vibration of the tongue rail，and the grave impact of the system will occur when the vehicle passes through the severe wearing frog.