The invention discloses a semi-automatic paint spraying machine and belongs to the technical field of paint spraying equipment. The semi-automatic paint spraying machine comprises a base plate assembly, a rotating assembly, spraying frame assemblies, spraying gun assemblies, an air supply device and a control box. The base plate assembly comprises a base plate and supporting rods. The rotating assembly comprises a cross-shaped rotating frame, a pneumatic motor, a holding frame assembly, a push assembly and a fixing seat. The spraying frames assemblies are arranged at the upper end of the base plate assembly and used for clamping the spraying gun assemblies. Each spraying gun assembly comprises a spraying gun and a spraying gun air cylinder. The control box comprises a box body, an electro connecting pressure gauge installed in the box body, a first electromagnetic pneumatic valve, a second electromagnetic pneumatic valve, a first time relay and a second time relay. According to the semi-automatic paint spraying machine, through a simple and compact mechanism and low cost, semi-automatic spraying over general parts such as reflecting mirrors is achieved, the labor intensity is lowered, the influence of gunner factors on the product quality is solved, and corporate profitability is improved.