Abstract: The acquisition of electrocardiological signal is one of the key technologies in body surface potential acquisition system.Based on the hardware platform of the 128-channel body surface potential acquisition system,this article puts forward an algorithm of electrocardiological signal acquisition and implements it on Win9x.In the implementation,VxD and lock memory technologies are used,and also an algorithm to access critical resource is introduced.The result shows this algorithm is concise and efficient.This software fully takes advantage of the idle time which the hardware platform brings about and a high real time performance has been achived.This software is developed on VC and VtoolsD.