Excavation of medium and small section extra-hard rock tunnels in water conservancy projects is often accompanied by difficulties in construction and low excavation efficiency.Based on the Fengdian-Pengdian reservoir connected emergency water diversion project,the drilling blasting scheme for the excavation of small-section extra-hard rock tunnel was studied.The field tests of different cutting blasting schemes were carried out and the technical scheme of combining multi-hole straight hole cutting blasting with air interval charging smooth blasting was proposed,and the specific drilling blasting parameters were determined.The field application results show that the combination of multi-hole straight hole cutting technology and air interval charge smooth blasting technology has good excavation forming effect,relatively flat excavation contour surface,basically no underbreak,and the maximum overbreak is about 20 cm,which realizes the safe and efficient excavation of the small section extra-hard rock diversion tunnel.