The invention discloses an anti-external force monitoring early warning method of an electric transmission line based on image recognition. According to the method, on the basis of an original electric transmission line remote monitoring system, an image recognition analysis module, an early warning information processing module and an early warning information display module are additionally arranged, an image recognition technology is used for analyzing data collected by a monitoring device, and the analysis result is transmitted to monitoring personnel in time in an early warning mode. The monitoring early warning method includes the following steps of (1) receiving an image, (b) preprocessing the image, (c) setting a warning trigger rule, (d) detecting a target, (e) analyzing the target, (f) conducting automatic alarm, (g) processing alarm information and (h) previewing a warning image and examining the image. The anti-external force monitoring early warning method of the electric transmission line based on image recognition has the advantages that cost is low, the image recognition method is simple, anti-external force monitoring data of the electric transmission line can be analyzed and calculated in real time, the abnormal condition on site can be subjected to quick early warning, and thus good economic benefits can be achieved.