Abstract: The idea of open architecture was introduced into the research of agricultural robot controller, and the hardware and software requirements of the open architecture controller were analyzed. The PC+DSP (Personal Computer & Digital Signal Processing) mode of the open architecture was adopted to construct the hardware of the open architecture control system with PC and PMAC (Programmable Multi-Axes Controller). Under the RTLinux (Real Time Linux), a kind of real-time operation system, the PMAC device driver and control software were developed to establish the open architecture control system of agricultural robot. The xy platform with two freedoms was controlled by this control system. With these control parameters (proportional gain is 19000, integral gain is 1000, derivative gain is 1000, velocity feedforward gain is 4700, acceleration feedforward gain is 20) the xy platform had ideal transient performance, small position and velocity error. It took 28.03 s and 30.28 s to complete the same task under RTLinux and Linux respectively. The test results proved that the open architecture control system of agricultural robot was real time and had good control performance.