Abstract: The purpose of this research was to acquire the valuable consumption power of corn straw chopping in the field at different feeding speeds because it was the main parameter for selecting suitable engine of corn harvester machine. It was also to make clear the functional relationships between the parameters, such as consumption power, feeding speed and moisture content of corn straw. By means of wireless data acquisition system, a new method for real-time measurement of consumption power was applied in this paper. The test results show that when the feeding speed of corn straw is 1.91 kg/s, the maximum consumed power could reach 12.04 kW which was 54 percent of engine output power. It was also found that consumption power increased as the feeding speed rose and moisture content had great influence on consumption power. The field test proved that wireless data acquisition system was safe and convenient.