The multi-function hydraulic control valve adopts a Y-shaped wide-body streamlined double-chamber design, divided into two main categories: diaphragm type and piston type. Depending on the functional requirements, it can be transformed into a multi- function pump control valve, remote control float valve, adjustable pressure reducing and sustaining valve, safety pressure relief/sustaining valve, electric control valve, etc., by changing the connection form of external pilot valves and conduits.