YLC-6M Radar is highly mobile, fully solid-state, 2D, median and low altitude surveillance radar, which adopts fully solid-state, full coherent, pulse compression, moving target detect system. The radar has perfect performances and possesses advanced technical features such as high mobility, high reliability and high automatization degree. The maintenance of the YCL-6M Radar should be performed at the radar site. This technical book describes mainly the contents and methods of various grades of maintenance at radar site. The radar should be sent to the median depot for major overhaul after 10 operation years, the major overhaul description is comprised in the range of this book. Under the condition of daily use, the maintenance schedule of YLC-6M Radar may be divided roughly into the daily maintenance, weekly maintenance, monthly maintenance and annual maintenance as per the time, but the time is not the most important thing, it means only that after certain operation time, the radar should be checked and maintained to keep the good performance and find the hidden trouble.