With the rapid development of concrete external reagent technology, the requirement for weighing precision of concrete mixer plant is higher and higher. Therefore analog digital converter and CPU with higher performance is required for designing controlling system. Power supply and PCB (Printed Circuit Board) with higher performance is required for assuring high weighing precision. The increase in commerce concrete industry has created a need for yielding efficiency of concrete mixer plant with higher speed of disposing data and transmitting data. We studied the achieving method of hardware system based on microprocessor and CAN-BUS in the scientific research item of concrete mixer plant controlling system. Firstly, this thesis presented a overview of the state of art in concrete mixer plant controlling system and the problem required to be resolved, and introduced the recent development in field-bus technology and the specifications of CAN-BUS, proposes a novel solution to improve the performance of controlling system. And then, the principles of concrete mixer plant controlling system, primary parts and its function are also introduced in this paper. Secondly, each module’s functions and the meanings for obtaining these functions, the applications of the related chips in the controlling system developed in this paper, especially for critical sensors, amplifier, analog digital converter and CPU, were illustrated in details. And in-system-program technology applied in this controlling system was introduced and its merits were also demonstrated. Then detailed representations for CAN-BUS principle, CAN controller, CAN high-speed transceiver, and design project for CAN-BUS interface were given. Finally, the cue of the design for switching value input and output interface circuits was given, and then a circuit in accordance with the thought of the design produced. Then the capable anti-disturbance measures adopted in hardware and software in this system was discussed. The practice shows that this hardware system designed in this thesis can not only meet the controlling system functions of concrete mixer plant, but also enhance the weighing precision of the concrete mixer plant by 10 times, simultaneously speeding up its data transmission greatly which will bring up a high efficiency. Thanks to these improvements, the overall performance of the concrete mixer plant increased effectively.