The invention relates to a process for a casting oil distribution disc of a vane pump, which belongs to the precision casting production process of hydraulic industry. The process adopts a wet mold molding composite casting process of preparing core by pre-coated sand, which comprises process design, mold design and manufacture, core preparation, sand core assembly, modeling, casting and sand removal and is characterized by respectively blowing and assembling with three to six sand cores, integrally making out an oil channel on a work surface, and placing a bonding surface on a finish surface. For the cast product casted by the invention, no fash existed, the oil channel is smooth, and the noise of the vane pump is reduced. The invention also can be applied in casting of oil distribution discs of PFX31, PFX41, PFX51 and the like, such as manufacture of oil distribution disc of various vane pumps. Therefore, the invention can remarkably improve the quality of oil distribution disc casting, and then remarkably improve the quality of vane pump product, and has significant economic and social benefits.