Abstract: Abstract: Because of its high efficiency and leveling precision, the laser leveler for paddy fields has received widespread attention in the mechanization of rice planting. The laser receiver is the elevation sensor component of a laser leveler for paddy fields, and the effective distances of the laser leveler for paddy fields are mainly decided by the noise-rejection performance of the photoelectric conversion and amplifier circuit.In extension work, due to strong solar irradiance and vibration the laser receiver may output wrong height position information, reducing leveling precision and work efficiency. In order to improve the reliability of elevation measurements, the photoelectric conversion and amplifier circuit of the laser receiver were optimized by using the experimental methods in this study.Laser receiving distance, energy conversion, and the noise and frequency characteristics of the laser receiver were selected as experimental variables. 2CR93 silicon photoelectric cells were selected as the laser photoelectric conversion element in this research. The laser pulse energy received by the silicon photocell was converted to an electrical signal. The signal energy is determined by the optical filter mode, laser spot and sweeping duration across the silicon photocell. As the receiving distance increases, the diameter of the laser spot expands, and both the sweeping duration across the silicon photocell and the laser energy received by the silicon photocell decrease. With increasing receiver distance, the short circuit current and open circuit voltage of the silicon photocell were obtained by experiments under two optical filter modes. When the receiving distance was over 175 meters, the short circuit current of the silicon photocells were approximately equal under each filter mode. When the receiving distance was over 50 meters, the open circuit voltages of the silicon photocells were also approximately equal. The bare 2CR93 silicon photocell was used as direct photoelectric converting device. With a 100 μH external inductance, the photoelectric conversion signal was modulated into a sinusoidal signal. With 4 parallel silicon photoelectric cells, the modulation frequency was 63.9 kHz. With 8 cells, the frequency was 43.5 kHz. The 2CR93 silicon solar cell equivalent diode capacitance was 16 nF. The laser receiver receives the laser signal and other external noise, including the mechanical vibration noise, solar irradiance noise and various electrical noises. The photoelectric conversion noise experiment result shows that with increasing background solar power, the laser signal peak value decreases and the noise peak value rises. Vibration noise affected only the low-frequency system.According to the test results, the photoelectric conversion circuit and amplification circuit parameters were optimized in this paper. The appropriate 100 μH inductance was selected; the photoelectric conversion signal was modulated into a sinusoidal signal. A smaller bandwidth could reduce the solar noise interference on the laser receiver; with an optimized, infinite-gain, multiple negative feedback, two-order bandpass amplifier circuit parameters could reduce vibration noise.Field testing results showed that when the transmitter was a Futian KF308, rotating frequency was 600 r/min, a multilevel, narrow-band amplifier can reduce the noise caused by solar irradiance, and the bandpass amplifier can reduce the noise caused by mechanical vibrations. The optimized laser receiver met height position requirements of a laser leveler for paddy fields.