Fracturing physical simulation experiment method for making new fractures between old fractures of horizontal well

The invention discloses a fracturing physical simulation experiment method for making new fractures between old fractures of a horizontal well. The fracturing physical simulation experiment method comprises the following steps that (1), the type of a test piece and the number of sections of staged fracturing are determined according to experiment requirements, drilling and grooving are carried outon the test piece according to a preset gap between the fractures, and a liquid injection pipeline is fixed in the test piece; (2), the test piece is placed in a large-size rock triaxial mechanical property testing device, and three-way confining pressure is applied to the test piece; (3), liquid is injected into the pipeline of the old fractures through a liquid injection system, the old fractures are pressed open and extend, and the hydraulic pressure in the old fractures is maintained through the liquid injection system; (4), liquid is injected into the pipeline of the new fractures through the liquid injection sy