The invention discloses a separate-layer fracturing stage number optimization method for a low-permeability compact reservoir. The separate-layer fracturing stage number optimization method comprises the steps that 1, a single well X fracturing position is divided into N transformation small layers; 2, assuming that the hydraulic fracture morphology is double-wing symmetrical cuboids, the corresponding hydraulic fracture transformation volume V is obtained under the certain fracturing liquid amount V and the discharge amount Q; 3, the N transformation small layers are divided into M fracturing sections from the point of fracture extension; 4, the fracturing liquid amounts V, the discharge amounts Q and the transformation volumes V corresponding to the fracturing liquid amounts V and the discharge amounts Q are obtained under different fracturing stage numbers; 5, the production income present value R of a single well X for three years is calculated under the different fracturing stage numbers and transformation volumes; 6, the hydraulic fracture transformation cost C is calculated under the different fracturing stage numbers; and 7, after fracturing is conducted, the production net present value (NPV) for three years is calculated, the relation curve of the different fracturing stage numbers and the NPVs is drawn, and the optimum fracturing stage number of the single well X is determined on the basis of the maximum NPV. The separate-layer fracturing stage number optimization method for the low-permeability compact reservoir is reliable in principle, convenient to operate and capable of providing a feasible method for production increase and transformation of oil and gas pools.