To develop a small agricultural machine location system for small paddy fields in the south of China, we have designed a laser receiver for farmland laser & three point location system. The laser receiver adjusts its receiving target rotation angle in real time through the servo mechanism, to ensure that it can effectively receive the signal transmitted from the laser emission source. Meanwhile, in order to accurately identify the laser spot center of the target, we have studied, the laser spot preprocessing algorithms based on the arithmetic mean filter algorithm, median filter algorithm and α-β filter algorithm. The laser receiver was fixed on the transplanter and tested dynamically. The result shows that the laser receiver can receive and recognize the laser signal accurately when the transplanter moves at different speeds such as 5,12,20 cm/s in the distance of 100 m, in the meantime, it can reflect the moving state of the transplanter in real time.