RTV is one of effective methods for power transmission equipment external insulation properties improving.However,the performance of RTV coating was affected by spraying operation,which was mainly artificial spraying on site.In this paper,an automatic spraying equipment was developed to deal with uneven coating thickness,flow and other phenomena of artificial spraying.The device can help the spraying gun achieve circular,up and down and swinging three-dimensional motion by setting up the gun's posture parameters.After spraying,spot detection found that artificial spraying thickness difference is quite large,while automatic spraying thickness is relatively uniform,and the automatic spraying equipment can effectively improve the RTV coating quality and efficiency.