A　pulsed　Nd:YAG　laser　with　high　average　power　is　presented.　The　influence　of　offset　angle　of　rods　in　six　rods　series　connection　resonator　and　the　master　oscillator　power-amplifier　(MOPA)　system　consisting　of　four　rods　oscillator　and　two　rods　amplifier　are　investigated　theoretically.　And　the　tolerances　of　offset　angle　are　compared.　It　can　be　seen　from　the　investigation　results　that　MOPA　system　reduces　the　requirement　of　precision　of　series　connection.　With　the　same　offset　angle,　the　deviation　of　optical　axis　of　the　MOPA　system　is　less　than　that　of　six　rods　resonator.　It　is　helpful　to　improve　the　security　performance　of　multi-rod　pulsed　laser,　and　obtain　high　average　output　power　and　high　pulse　energy.　A　MOPA　system　with　four　rods　oscillator　and　two　rods　amplifier　has　been　used　in　the　experiment,　and　the　offset　angle　of　all　rods　is　adjusted　in　the　tolerance.　With　input　electric　power　of　87　kW　and　a　duty　cycle　of　17%,　a　maximum　average　output　power　of　3011　W,　a　peak　power　of　17.7　kW,　a　maximum　single　pulse　energy　of　67　J　and　a　beam　parameters　product　of　25.2　mm·mrad　have　been　obtained.　The　electro-optical　conversion　efficiency　is　3.46%,　and　instability　of　the　laser　is　less　than　2%.