3D2A-S high pressure pump is improved on the basis of the pump 3D2. The characteristics are as follow: The volume of lubrication oil in crankcase increases which improves lubricity and oil temperature rise is low; The crankshaft diameter increases so that increases the strength of crankshaft and the transmission power is bigger, the output pressure of the pump is bigger, thus the application scope is wider; In power end, the crankshaft and connecting rod adopts forced lubrication with lower friction coefficient, good lubrication, stable driving, low temperature rise and suitable for long time continuous operation. The pump is applied to high pressure water jetting auxiliary flow cleaning, metallurgy descaling, powder metallurgy, shipping derusting, basic engineering, liquid transportation, engineering and pressure test for various rubber hose, metal tube and oilfield drilling equipment as well. It can pump clear water, emulsion, and other chemical liquid similar with clear water.