This paper discussed the character of the rapier loom’s weft yarn inserting motion and the reality about process of the weft yarn inserting motion. On the base of separated-reed rapier loom , This paper proposed the project about electric weft yarn insertion and discussed the program to realize the inserting motion . the designing and making of the insertion control circuit is described in detail.During analyzing the motion of weft yarn insertion, this paper use the virtual machine method, Simplified some question those are answered with mechanism theory.About the question of controlling the weft yarn insertion, this paper presented the compound control algorithm to make the accuracy of track in the reasonable range.The one of main contents in this paper is the making of controller for weft yarn insertion. This study uses microprocessor system to realize the function of the electric weft yarn insertion’s circuit.The problem about anti-interference performance of the control circuit is very important. In hardware aspect, this paper use optical-electric insulation method stronger the signal of optical-electric encoder and insulate the infection of out load for main circuit successfully. In software aspect, the software trap and some other methods are used.The content studied by this paper is an exploration of renovating the weft yarn insertion system for rapier loom. The study is a whole new design of equipment of weft yarn insertion. The new equipment is drive by motor directly. The structure is simple, the weight is light and noise is small, the precision of controlling is higher, The adjustment is more convenience. It improved the level of rapier loom automation.