With the increase of demand for organic vegetable, automated mechanical weeding machines are more and more in need. According to the working condition and requirement of weeding operation for transplanted vegetable crops, an electric driven weeding robot system was developed and tested. Carried by a middle or lowhorsepower tractor, the weeding robot could efficiently remove inter and intrarow weeds. The system was equipped with a machine vision system, which acquired and processed field images in real time to recognize crops and obtain their locations. Four electric motors were used to drive three crescent weeding blades and the steering mechanism to avoid crops and follow crop rows. The system had two microcontrollers to control weeding blades and the steering mechanism separately. The controllers fused bladecrop distance, phase position of motors and forward speed of robot, to accurately guide the weeding blades avoiding crops and tracking the rows. To evaluate the working performance of weeding robot, tests were conducted on concrete road surface and in field respectively. Results of the tests indicated that the robot could remove 90% weeds while the crop damage rate was less than 10%, when the speed was under 1.5km/h and plant spacing was above 0.35m. Compared with hydraulic driven weeding machine, it had lower energy consumption, less pollution and better servo property.