The invention discloses a refracturing method by naturally selecting dessert temporary blocking size for a horizontal well. The refracturing method comprises the steps that a well with certain geologic reserves is selected, and geological dessert areas of the whole horizontal well which needs to be subjected to refracturing are ruled again; a new rock mechanics crack initiation order is predicted;the dessert area with rich accumulation of oil and gas and with the best physical property is found, and a first fracture is pressed to be open; the first fracture is blocked through a temporary blocking agent, fracturing liquid is pumped into continuously, the pressure rises, the dessert area of the secondary grade is selected, and a second fracture is pressed to be open; multiple fractures of athird fracture, a fourth fracture and the like are sequentially pressed to be open, and fracturing of the multiple fractures with naturally selected desserts in a segment is realized; and meanwhile,the powder-like high-strength water-soluble temporary block agents are put into the fractures so as to form temporary blocking on the end of the main fracture, the net pressure in the fracture is increased, the micro-fracture which cannot crack originally is pressed to be open, or the new branch fracture is formed, and a larger transformation size is obtained. According to the refracturing method,the defect that a sleeve is deformed, and consequently, a downhole tool cannot be tripped into is effectively overcome, and recovering and increasing of the productivity of the horizontal well are facilitated.