Abstract: The paper proposed a realization method of real-time motion pause function of ACS motion controller. The method makes small program segments be downloaded point by point in the motion instruction queue by splitting large program block into small time segments and adding conditional control statements between the adjacent small program segments, so as to control the whole program effectively and realize real-time motion pause function. The method has been applied in CNC system of spring coiling machine based on ACS motion controller with a perfect effect of real-time motion pause and no accumulative error.