The invention provides a method for increasing the length of hydraulic fracturing double-wing cracks. The method includes a step 1 of performing static and dynamic rock mechanics testing on an implementation well and performing correction to obtain longitudinal ground stress data of a reservoir, a step 2 of performing simulation optimization to obtain the best perforation plan for preventing the height of cracks from being out of control and increasing the length of the cracks, and a step 3 of performing physical simulation of proppant migration laws under different fracturing fluid viscosities, different construction displacements and different sand ratios and obtaining a mathematical model. The method, in a fracturing process, can effectively increase the length of the cracks by designing the viscosity of a fracturing fluid and the construction displacement and using a matched a crack height design.