As a special machinery for field breeding experiments, the plot seeder has a very important role in improving efficiency of breeding, reducing labor intensity and costs, as well as ensuring scientific nature and accuracy of test results. In order to improve the mechanization and automation level of the plot seeder and solve the problem that it is difficult to adjust the operating parameters, a wheat plot seeding control system based on STM32 was developed. The system was mainly composed of an Android mobile phone terminal, main controller of STM32, lifting system of storage cylinder, control system of cone compartment tray for seed meter, and control system of seed dispenser. The stepper motor and direct current motor speed control model were established. And human-computer interaction interface was designed, which was used to set working parameters. For checking up the performance of wheat plot seeding control system in plot seeder and gaining better combination of parameters, indoor tests were carried out at three cone compartment tray rotation speed of 4r/min, 6r/min and 8r/min, and four seed dispenser rotation speed of 1100r/min, 1250r/min, 1400r/min and 1550r/min. Test results showed that the cone compartment tray rotation speed, seed dispenser rotation speed, and the interaction of them had a very significant effect on the uniformity between rows by the analysis of variance. With the increase of rotating speed of the cone compartment tray, the variation coefficient of the uniformity between rows was increased. With the change of rotating speed of seed dispenser at 1100~1550r/min, the variation coefficient of the seed uniformity was reduced firstly and then increased. When the rotating speed of the cone compartment tray and seed dispenser was 4r/min and 1250r/min respectively, the variation coefficient of uniformity between rows was 4.53%, of which the uniformity between rows was better and the grain damage rate was smaller. This control system could provide a research basis for the automation and intelligent control of plot seeding.