The microcomputer harmonic suppression device is a compact, intelligent harmonic suppression unit developed and manufactured. It utilizes the ATmega128 microcontroller from the U.S. company Atmel, featuring a Reduced Instruction Set Computing (RISC) architecture, as the sampling, logic judgment, and control center (CPU). It outputs through high-power, non-contact harmonic suppression elements, and interfaces with the user via a dot matrix LCD display, signal indicator lights, touch buttons, a miniature printer, and an RS485 field communication bus. Equipped with intelligent software, it forms a technologically advanced and user-friendly "dumb" diagnostic, harmonic suppression, and recording unit.