Abstract: An isolation automatic control valve is formed by disposing an isolation valve of very simple structure in the inlet and outlet passages of a main valve or in the passage joining a main valve and its pilot valve, which not only controls normal operation during automatic controlling but also can isolate the main valve from the pilot valve for on-line maintenance while simultaneously controlling operation of the main valve manually or automatically. The isolation valve includes a throttling function to enable the main valve to acquire various control parameters. The present invention enumerates nine embodiments of different pressure, flow and direction control valves, each being applicable in various fields of general purpose valves, hydropneumatic valves and instrument valves. The present invention exhibits compact structure, simple piping, adjustable parameters and convenience in operation.