The principle of numercial control (NC) interpolation is the teaching focal point as well as the teaching difficult of the “NC System and Principle” and “NC Technology”. For the current status of lacking experimental teaching equipment of NC interpolation principle in colleges and universities,based on the LabVIEW virtual instrument development platform,an experimental simulation teaching system of NC interpolation principle is developed. This system can achieve linear interpolation and circular interpolation computing by the point-to-point comparison method and the digital integral method in the first quadrant,and dynamically display the trajectory of the interpolation and theoretical straight line or circular arc curve in real time,which meets the needs of experimental teaching and training.