Abstract: In order to solve the sealing problem in hydraulic fracturing experiments of rock sample under high temperature and high pressure (HTHP)， theoretical analysis， numerical simulation and physical experiment were used to design a new type of sealing hydraulic fracturing experiment based on wedge-shaped metal buckled structure and its sealing effect under water injecting was analyzed by simulation. Furthermore， the HTHP hydraulic fracturing experiments were successfully conducted by using this proposed sealing technique. The results show that the high temperature， high pressure and high water-injecting pressure are all favorable conditions for the further sealing of the wedge-shaped buckled structure. Increasing the water-injecting pressure can realize the compressed sealing process. Finally， the hydraulic fracturing experiment of large-size rocks under HTHP is successfully conducted， which in turn verfies the sealing effect of this structure. The multiple hydraulic fracturing characteristics of rock is revealed by using this sealing technique.

Key words: geothermal energy development; high temperature and high pressure; granite; hydraulic fracturing; sealing; sealing technique