Aiming　at　the　problems　of　large　thermal　resistance　and　uneven　light　output　of　high-power　vertical　cavity　surface　emitting　laser　(VCSEL)　array,this　paper　studies　the　action　mechanism　of　ohmic　contact　resistance　of　p-GaAs　layer　and　the　method　of　reducing　ohmic　contact　series　resistance,　so　as　to　improve　the　uniformity　of　light　output　power　of　VCSEL　array.　Based　on　three　commonly　used　ohmic　contact　metals　Ti/Au,　Ni/Au　and　Ti/Au/Ti/Au,the　effects　of　metal　thickness　and　metal　combination　on　p-type　ohmic　contact　resistance　are　studied.　Combined　with　plasma　surface　treatment　process,　the　iner-face　state　of　metal/p-GaAs　is　improved,　the　effect　of　metal/p-GaAs　interface　state　on　ohmic　contact　resistance　is　studied.　The　experimental　comparative　analysis　shows　that　the　specific　contact　resistivity　of　ohmic　contact　of　metal　Ti/Au　structure　electrode　is　the　lowest,which　is　3.　25X10　Cl　•　cm＂.　Based　on　the　metal/　semiconductor　contact　potential　barrier　model,　the　interface　potential　barrier　can　be　reduced　by　12.　6%　(0.269　2　eV　to　0.235　3　eV)　by　surface　plasma　treatment,　and　the　plasma　bombardment　power　can　regulate　the　potential　barrier　and　density　of　states　on　the　metal/semiconductor　interface.　©　2023　Board　of　Optronics　Lasers.　All　rights　reserved.