A chute mass flowmeter of granular materials was designed based on capacitance method and according to the difference in dielectric properties between granular materials and air to achieve online automatic measurement of the mass flow rate of granular materials in the chute.The device was equipped with an STM32 microcontroller， a capacitance-to-digital Converter chip AD7746， and a plate conversion circuit with MT8816 as the core chip to build a data acquisition system， achieving effective acquisition of capacitance of eight-plate rotary excitation sensors.A test bench of mass flowmeter was built.Maize， wheat and granular compound feed were used to calibrate the relationship between the mass flow rate and the value of cumulative capacitance.The models of predicting the mass flow of three kinds of granular materials were constructed， with determination coefficient R² of 0.990 4， 0.993 9， and 0.987 9， respectively.The results of verifying the accuracy of chute mass flowmeter showed that the average relative error （MRE） of measurement accuracy for maize， wheat and granular compound feed was 3.11%， 3.76%， and 3.75%， when the inclination angle of the chute was 15°， 25°， 35°， 45°， and 55°， the mass of maize and wheat mass was 30， 50 and 70 kg，the mass of granular compound feed was 30， 50， and 65 kg， respectively.It is indicated that it is feasible to use the capacitance method in the online measurement of mass flow rate in the process of transporting granular materials through a chute， which can achieve the automatic online measurement of the mass flow rate of granular materials.