The utility model discloses an electromechanical liquid coupler of exciting sloping cam plate variable formula of direct current stator, including braced system and connected variable system, mechanical energy conversion system, hydraulic pressure ability conversion system and electric energy conversion system, braced system includes casing and valve plate etc, the variable system is including adjusting jar, connection block etc, mechanical energy conversion system includes transmission shaft and preceding, rear bearing, hydraulic pressure can include cylinder body, sloping cam plate and plunger etc. By conversion system, electric energy conversion system is including changeing subcoil, stator core, excitation winding, lead terminal etc. Stator core and excitation winding fix in the big inner chamber of casing, adjust the jar and fix in its little inner chamber, transmission shaft and cylinder body are acted on by the sloping cam plate through the synchronous rotation of splined connection, the plunger sucks or export hydraulic oil along axis reciprocating motion, concrete during operation, and the interconversion between mechanical energy, hydraulic pressure ability and the electric energy through the adjusting bolt regulation discharge capacity and the hydraulic pressure flow direction, is realized to the external direct current of lead terminal. Have advantages such as compact structure, conversion efficiency is high, loss of pressure is little, because application demand and industrialization broad prospect are strengthened to the adjustable adaptability of discharge capacity.