Combine harvester is an important tool of agricultural production. The feed rate of harvester has always been a hot topic in the area of automatic control. By analyzing the operation mode of harvester, the change model of feed rate of harvester was established. A monitoring system for state parameters of harvester was designed and developed. The system includes grain flow sensor, header height sensor, grain moisture content sensor, feed rate sensor and global navigation satellite system. Taking wheat as the experimental object, a field experiment was carried out in North China to verify the monitoring accuracy of feed rate in different yield moisture content plots. The parameters such as feed rate, yield, moisture content and operation speed were also collected simultaneously. The average relative error of feed rate monitoring was 8.55%. Taking the feed rate of harvester as the control target state and the operating speed of harvester as the control quantity, the feed rate of harvester was simulated by using the method of model prediction. Grey wolf optimization algorithm was used to optimize the weight matrix of quadratic programming. The simulation results showed that the MAE of feed rate control was less than 0.1kg/s after the weight matrix optimization, which was decreased by 38.1% on average. The error of feed rate control was inversely proportional to the yield of the harvest area and proportional to the moisture content. The control effect was better in harvest areas with even wheat growth.