A new type of NC machine tool fault monitoring system was designed. Through installing a variety of sensors in the positions of the NC machine tool where were prone to failure , multiparameter comprehensive monitoring for NC machine tool was carried on. Data acquisition module was used to realtime collect the various dynamic parameters which were transmitted to the PC through wireless way. The corresponding fault monitoring software was installed in the PC, it could display fault information through the software interface and alarm promptly.Experimental results show that the sensor network technology applied to the NC machine tool fault monitoring system, can decrease the rate of machine downtime, improve the utilization rate of machine tools and prevent some early recessive fault.