According to the failure mechanism of ore rock in blasting and the principles that the explosion stress wave produced the transmission and refraction on the interface between ore rock and fillbody,the authors present the variant medium interface blasting technique and put it into use successfully in lianjiang silver mine,with a good blasting result. This technique is better in solving the technical difficulty in preventing the fillbody from failure when conducting a blasting in upward drift stoping with cemented filling.