A micro-spectrometer without moving parts that can be manufactured through micro-opto-electro-mechanical system techniques is developed, and the interference system is introduced. The fabrication of the micro multi-mirrors, which is the core part of the system, is investigated and wet etching of silicon in KOH solution is testified to be a good method. The root mean square surface roughness of the reflect surface made up of Si planes （111） through wet etching is less than 10 nm.