With the continuous progress of science and technology, China is transforming into the field of industrial automation, striving to contribute to the liberation of labor force and the realization of assembly line industrial automation. The operation of the traditional automatic electromechanical control system(AECS) still needs a lot of manual operation, which is difficult to realize the development of all automation of electromechanical control. The new AECS proposed at present is to realize the automation, intelligent and remote control of electromechanical control system, and truly take the control system as the center for electromechanical control production.Therefore, this paper puts forward the design and application of AECS based on PLC technology. Through research, this paper expounds the AECS based on PLC technology and its application. PLC technology can realize automation and integrated control in system control, compact structure, and can accommodate the conversion of many digital signals to realize its control function of the system, study the software design of AECS, mainly design the input interface and output interface. In order to understand the application and performance of PLC technology in automatic electromechanical system, this paper compares and analyzes the fuzzy PID control error of PLC technology and the performance of AECS based on PLC technology with traditional AECS. The experimental results show that in the comparative analysis of simulation experiments between the performance of AECS based on PLC technology and traditional AECS, the proportion coefficient of traditional AECS is 1.63, the integral time constant is -1.06, and the differential time constant is 0.29, while the proportion coefficient of AECS based on PLC technology is 0.56, the integral time constant is 0.37 and the differential time constant is 1.18. The deviation of AECS based on PLC technology is smaller than that of traditional automatic electromechanical control, and the static error is also smaller, but its response speed is faster and its performance is better.