A hydraulic transmission device of a mobile ground anchor vehicle comprises a hydraulic oil tank, a filter, a gear pump, a three-position four-way hand-operated direction valve, a leg four-linked multi-way valve, a two-way hydraulic lock, a leg hydraulic cylinder and an upper five-linked multi-way valve, wherein one end of the three-position four-way hand-operated direction valve is sequentially connected with the hydraulic oil tank, the filter and the gear pump, and the other end is connected with the leg four-linked multi-way valve and the upper five-linked multi-way valve; the leg four-linked multi-way valve is sequentially connected with the two-way hydraulic lock and the leg hydraulic cylinder; and the upper five-linked multi-way valve is connected with a turntable hydraulic motor, a two-section telescopic hydraulic cylinder, a three-section telescopic hydraulic cylinder, a ground anchor rotating motor and a lifting hydraulic cylinder respectively. According to the hydraulic transmission device of the mobile ground anchor vehicle, the three-position four-way hand-operated direction valve is mainly added, so that flows of an upper hydraulic system and a lower auxiliary system are matched, pressure distribution of different hydraulic execution components is optimized, the service life of the whole hydraulic system is prolonged, and the hydraulic transmission device has the characteristics of reasonable design, convenience in mounting, easiness in operation, simplicity in maintenance and the like, and is widely applied in hydraulic transmission engineering of the mobile ground anchor vehicle.