In order to improve the complexity of artificial fractures during deep shale gas fracturing and expand the volume of reservoir transformation, the design and application research of volume fracturing technology were carried out for deep shale gas in southern Sichuan. Based on the reservoir fracture width parameter, a composite temporary plugging material is formed by combining proppants, temporary plugging agents, and temporary plugging fibres. Through the independently developed proppant transportation and fracture plugging simulation device, the combination characteristics of the composite temporary plugging material were comprehensively evaluated, the combination parameters were optimised, and the injection strategy was designed according to the fracture control requirements to form a volume-promoting fracture process. It has been successfully applied and verified in the fracturing construction of deep gas well L3 in southern Sichuan. The results show that 3–9 mm fibres can adaptively seal 0.5–3 mm fractures, and for 4 mm fractures, when the 9 mm fibre concentration is ≥ 0.4%, the sealing pressure can exceed 20 MPa; When the closure stress exceeds 20 MPa, the flow capacity decreases by less than 5%. The application results of deep shale gas construction in southern Sichuan demonstrate that volumetric fracturing technology effectively increases net pressure and promotes the formation of artificial complex fracture networks, resulting in a 21% increase in EUR per kilometer after fracturing compared to neighbouring wells. The volumetric fracturing process uses proppants as the main body to achieve large-scale controllable temporary plugging and turning inside the fractures, providing an effective method for the efficient construction of artificial complex fracture network systems in the transformation of deep shale gas reservoirs.