The deflector jet servo valve is a two-stage four-way electro-hydraulic flow servo valve, adopting a two-stage hydraulic amplification structure. The first stage is a deflector-type hydraulic amplifier, composed of a jet plate, a deflector, etc., and the second stage is a spool valve hydraulic amplifier. Deflector jet servo valves are widely used in military and civil aircraft flight control, electromechanical and engine control fields, and can be extended to aerospace, maritime, ordnance and other defense fields as well as civil industrial fields.