Theoretical study and site ventilation tests are made on gallerytype jet construction ventilation technology on basis of Jinping Auxiliary Tunnel (west side) of Jinping hydropower project and conclusion is made on such key technologies as the type selection and layout of gallerytype jet ventilation fans and ventilation management. The calculation formula of the required air flow rate and the number of the fans and the principle of selecting proper values for the relevant parameters are summarized. The construction ventilation technology has been successfully applied in the deadend driving of the 9300mlong twintube tunnel with internal combustion working mode and trackless transportation system, which demonstrates that all the indexes of the air inside the tunnel have met the national environment and health requirements and good economic and social efficiency have been achieved.