Research conclusions: The steady arm grade in initial state depends on the design parameter of track，the contact wire＇s rated tension，stagger，span length and the structure parameter of the steady arm． The rational determination of the design parameters，such as the contact wire＇s rated tension，stagger，span length is crucial to the safety and reliability of the steady arm grade． The cantilever should be designed and installed according to the calculated steady arm grade．Otherwise，the accuracy of the pre － configure calculation shall be affected，and even the adjustment of the pre －configure components in the site will be done． Taking the measures like the registration arm support and the wind － proof wire，can preferably ensure that the contact wire＇s geometrical structure still is in the allowed range under the compact of the running wind load and the operation safety of the pantograph，and make the registration safer and more reliable．