Abstract: The treating technique of high pressure composite groutig at fault f1096 lying in the depth of 103 m of TGP is presented. How to decrease permeability coefficient, and to reinforce the cracked zone of fault with pore - water and soft interlayer to meet requirements of engineering from the three aspects of chemical grouting materials, chemical grouting equipment and construction techniques were studied. Through composite
grouting, the deformation modulus of cracked zone of fault was enhanced from 200-300 MPa to more than 8 GPa, and the average permeability rate decreased from 24.4-140.23 Lu to less than 1.0 Lu. These indexes, i.e., deformation modulus E≥8 GPa and permeability rate after grouting q≤1.0 Lu etc., reach design requirements.