Abstract: Aiming at the disputes and concerns about water lock damage of fractured tight sandstone gas reservoir of Kuqa mountain front in Tarim oilfield, in this paper, by using laboratory experiment evaluation, microscopic mechanism demonstration and on-site production analysis, the damage degree and relief measures of water lock under high temperature and pressure are studied. It is cleared that the damage rate of water lock is 7.5%-40.8% under high temperature and high pressure conditions, and the damage degree is non-moderate and weak. The water lock are reduced slightly by adding waterproofing agent, which can not be eliminated, but it can be automatically removed with production. In this paper, a new understanding of water lock damage and release is obtained, which effectively supported the optimization of Kuqa piedmont transformation fluid system, and the field application has a significant effect of reducing cost and increasing efficiency.