The　effects　of　B　content　on　the　magnetic　properties,　corrosion　resistance　and　microstructure　of　sintered　Nd-Fe-B　magnet　containing　Dy　and　Ga　are　studied　in　this　work.　As　the　B　content　increases　from　0.88　wt%　to　0.94　wt%,　the　intrinsic　coercivity　(Hcj)　of　magnet　increases　at　first　and　then　decreases.　The　Hcj　exhibits　a　peak　value　of　22.19　kOe　at　0.92　wt%　B,　accompanied　by　the　remanence　(Br)　of　13.43　kGs　and　the　maximum　magnetic　energy　product　(BH)max　of　43.83　MGOe.　When　the　B　content　is　0.92　wt%,　the　grain　boundary　phase　(GBP)　between　the　main　phase　grains　simultaneously　attains　the　widest　width　and　the　lowest　Fe　content,　which　effectively　improves　the　demagnetization　exchange　coupling　between　the　adjacent　grains.　Meanwhile,　the　RE6Fe13Ga　and　Ia3-RE2O3　phases　in　this　magnet　exhibit　a　small　lattice　misfit　with　adjacent　main　phase,　which　helps　to　reduce　the　nucleation　of　reverse　domains　at　the　GBs.　The　corrosion　resistance　of　magnet　can　be　enhanced　by　increasing　the　B　content,　as　evidenced　by　the　elevation　in　open　circuit　potential,　the　decrease　in　corrosion　current　density,　and　the　increase　in　charge　transfer　resistance　in　3.5　wt%　NaCl　solution.　The　magnet　with　0.94　wt%　B　exhibits　optimal　corrosion　resistance.　By　optimizing　the　B　content　in　sintered　Nd-Fe-B　magnet　with　1.8　wt%　Dy　and　0.5　wt%　Ga,　an　intrinsic　coercivity　comparable　to　that　of　magnets　containing　3-5　wt%　Dy　and　0.91-0.98　wt%　B　can　be　achieved,　while　the　corrosion　resistance　is　also　enhanced　to　a　level　comparable　to　that　of　magnets　containing　6-7　wt%　Dy　and　1　wt%　B.