A　new　concept　of　diphase　oppositing　giant　magnetostrictive　self-sensing　actuator　is　put　forward,　combining　with　sea　water　servo　control　technology,　a　flapper-nozzle　force　feedback　sea　water　servo　control　valve　is　designed.　Bridge　analysis　model　based　on　variable　inductance　is　established,　dynamic　balance　separation　technology　for　giant　magnetostrictive　self-sensing　actuators　is　come　true　by　least　means　square　self-adapting(LSM)　algorithm.　With　the　real-time　separation　circuit　of　dynamic　balance　signal　based　on　digital　signal　processing,　the　simulations　show　that　the　self-adapting　algorithm　with　LMS　can　be　used　to　separate　the　giant　magnetostrictive　self-sensing　actuator　sensing　from　the　excitation　signal　totally　with　less　distortion.　In　addition,　based　on　the　Jiles-Atherton　physics　model,　quadratic　moment　domain　rotation　model　and　structural　dynamics　principle　as　well　as　the　dynamic　model　with　hysteresis　nonlinearity　for　servo　valve　is　established　to　determine　change　relation　between　actuating　coil　current　and　spool　displacement.　The　emulation　result　shows　that　the　actuator　has　larger　output　force　and　displacement,　which　can　meet　the　practical　needs.