The mixer truck is composed of a car chassis and a specialized device for concrete mixing and transportation. The chassis of the mixer truck mostly adopts the second-class universal chassis provided by the vehicle manufacturer. Its specialized mechanisms mainly include power take-off, front and rear brackets of mixing drum, reducer, hydraulic system, mixing drum, control mechanism, cleaning system, etc. The working principle is to extract the power from the car chassis through a power take-off device and drive the variable pump of the hydraulic system, converting mechanical energy into hydraulic energy and transmitting it to the quantitative motor. The motor then drives the reducer, which drives the mixing device to mix concrete.