As　the　continual　improvement　of　technology　and　beam　quality,　diode　laser,　with　poor　beam　quality,　no　longer　just　apply　to　pump　solid-state　laser.　As　a　kind　of　implement　of　laser　materials　processing,　high-power　diode　laser　has　been　used　in　manufacture,　as　a　brand　new　means　of　laser　processing.　Due　to　the　influence　of　inevitable　unstable　factors,　for　example,　the　temperature　of　water-cooler,　the　current　of　power　supply,　etc,　the　output　power　of　diode　laser　will　be　unstable.　And　laser　output　power,　as　an　important　parameter,　frequently　affects　the　performance　of　the　laser　beam　and　the　experimental　results　of　processing,　especially　in　the　laser　materials　processing.　Therefore,　researching　the　real-time　power　measurement　and　control　of　high　power　diode　laser　has　great　significance,　and　for　diode　laser,　it　would　improve　performance　of　itself.　To　achieve　the　purpose　of　real-time　detection,　traditional　measuring　method,　placing　a　power　sensor　behind　the　total-reflection　mirror　of　laser　resonant　cavity,　is　mainly　applied　in　the　system　of　gas　laser　and　solid-state　laser.　However,　Owing　to　the　high　integration　level　of　diode　laser,　traditional　measuring　method　can＇t　be　adopted.　A　technique　for　real-time　measure　output　power　of　high　power　diode　laser　is　developed　to　improve　quality　of　the　laser　in　this　paper.　A　lens　placed　at　an　angle　of　45　degrees　in　the　system　was　used　to　sample　output　light　of　laser,　and　a　piece　of　ground　glass　was　used　to　uniform　the　beam　power　density,　then　the　photoelectric　detector　received　an　optic　signal　and　converted　it　into　electric　signal.　This　feeble　signal　was　processed　by　amplification　circuit　with　a　filter.　Finally,　this　detected　electric　signal　was　applied　to　accomplish　the　closed-loop　control　of　power.　The　performance　of　power　measurement　and　control　system　was　tested　with　the　300W　diode　laser,　and　the　measuring　inaccuracy　achieved　was　less　than　+/-　1%.