The blockage problem often occurs in the clamping and conveying system of the peanut combine harvester, and it is extremely critical to do research on the working load of its hydraulic system. The working loads of the hydraulic motor of the driving system of the clamping and transportation of peanut seedlings were measured to obtain the typical load spectrum. According to the motor analysis of a large amount of test pressure data, three rational speeds of the output shaft, respectively, 310r/min, 360r/min and 410r/min were chosen. For a large number of the test data, the turning point extraction method was used to compress the load data to about 1/50 of the original. Then the load in the time domain can be transformed into range and mean load in the rainflow domain through the rainfllow counting method. And the maximum likelihood parameter estimation method was employed during the statistical analysis. The rotational speed of motor of 410r/min was determined as the typical working condition of the system according to the fitting test result. Because the mean and range load of the system pressure met the requirements of a normal distribution with a mean of 7.28, a standard deviation of 0.81, and a three-parameter Weibull distribution with a threshold of 0.32, a scale parameter of 0.30, and a shape parameter of 0.90. Due to the requirements of indoor bench test, mechanical parts testing of peanut seedling spreading conveyor system and the structure optimization design, the pressure signal of the system hydraulic motor was converted into torque signal. Then, the joint probability density function of the mean and range load was established based on the independence of mean and range. And on this basis, the two dimensional torque spectrum of the hydraulic motor output shaft was obtained by the load extrapolation method. Finally, combined with the actual test loading requirements, dimensionality reduction operation was performed on the two-dimensional load spectrum. And the one-dimensional program spectrum was transformed from the two-dimensional according to the variable mean method for the convenience of actual load test. The application of statistical analysis method of compiling of one-dimensional program would realize the reproduction of field operation load and provide a reliable data foundation for the bench test for indoor mechanical parts of peanut combine harvester.