According to the complex geological conditions of deep tight gas reservoir in Daqing oilfield, fracture developing in conglomerate and volcano rocks in the reservoir and strong water sensitivity; leakage, collapse, diameter shrinkage and drilling fluid property degradation while drilling at high temperature; friction, cuttings carrying and reservoir pollution in deep horizontal well drilling, as well as the high cost and late environmental protection pressure caused by the use of oil-based drilling fluid, on the basis of the analysis and summary of the previous experience, starting from the geological characteristics in tight gas reservoir and difficult points of deep horizontal well drilling, the technical measures for drilling fluid were clear. Though the study on inhibition of polyamine & polyether polyol and anti-sloughing plugging agent and working with new efficient independent developed drilling sealing material, a set of double poly amine drilling fluid technology was developed, which is suitable for horizontal well construction in deep tight gas reservoir. The laboratory studies and field application show that this drilling fluid system has ability of strong sealing