Passive Power Filters (PPFs) are vital equipments for harmonic pollution control, but optimal design of PPFs is a rather difficult problem of multi-objective optimization and evaluation. On the basis of our previous work in evolvable hardware, especially evolutionary design of circuits, a Uniform Design Technique (UDT) based multi-objective genetic algorithm was developed towards optimal design of PPFs. It is characterized by an efficient and effective encoding-decoding scheme based on the standard series of component values, a mechanism to integrate and evaluate multi-objectives based on UDT, weight-vectors adjusting and PSpice simulation, a UDT based multi-parent crossover operator to improve offspring quality and computation cost, and an adaptation technique for genetic parameters to maintain the individual diversity and track the GA process. It is shown by simulation results capable of searching out a set of effective design results of PPFs, which meet the main optimization objectives and reflect roughly interactions between them.