The invention relates to a resin sand casting molding core curing device and a curing method thereof. The resin sand casting molding core curing device comprises a bottom plate, a rotating motor, a conveying plate, a hanging support, a telescopic cylinder, a telescopic connecting plate and a spraying mechanism, wherein the rotating motor is arranged on the upper end surface of the middle of the bottom plate through a motor sleeve, the conveying plate is installed on an output shaft of the rotating motor, the hanging support is arranged on the top of the outer end of the bottom plate, the lowerside surface of the upper end of the hanging support is connected with the upper end of the telescopic air cylinder, the telescopic connecting plate is arranged at the lower end of the telescopic aircylinder, and the spraying mechanism is arranged on the bottom of the telescopic connecting plate. The device can solve the problem that when the existing resin sand is hardened, the molding sand isnot uniformly sprayed when the molding sand in a sand box is sprayed with a curing agent by manual operation, the curing agent can not be sprayed to the position of the sand pit, when the curing agentis sprayed, more waste is caused, and when the curing agent is manually sprayed, the spraying efficiency of the molding sand in the sand box is low due to the small spray mist generated by an atomizing machine.