An adaptive active noise control system based on micro-computer is presented in this paper. This system can supply an agile experimental platform for the research of different system construction and control algorithm. This paper adopts LMS algorithm as an adaptive filter controller，which can automatically compensate for the effect on noise control caused by the changes of the background noise，environment factors and electrical or acoustical parameters. It can accomplish notable broad-band noise attention. The results of experiments show that under the condition of two secondary sound resources arranged within free space，the maximum attention level obtained by the system is more than 40dB to the single frequency and barrow-band random noise from 50 to 400Hz.