This paper centers on researching the application of PLC mechatronics technology in building electrical automation

constructs a hierarchical control architecture with PLC as the core

and carries out the system design on the four levels of data acquisition

control processing

execution feedback and remote monitoring. By conducting experiments in the actual building environment

and comparing the traditional timing control with the PLC-based adaptive control strategy

the results show that the system shows significant advantages in terms of energy consumption reduction

load transfer and temperature regulation accuracy. The experiment verifies the effectiveness of PLC combined with mechatronics technology in the building electrical system to realize energy saving

consumption reduction and environmental comfort enhancement

which provides a theoretical basis and practical reference for the development of intelligent buildings and green energy-saving technology.