Nano-boron　nitride　(h-BN)　has　excellent　physical　and　mechanical　properties.　Due　to　its　stable　chemical　performance,　the　improvement　effect　on　the　properties　of　cement-based　materials　was　limited.　Therefore,　the　chemical　modification　method　was　used　to　prepare　functional　h-BN　to　improve　its　application　potential　in　cement-based　materials　in　this　paper.　The　hydroxylated　nano-boron　nitride　(h-BN-OH)　was　prepared　by　modified　pristine　h-BN　with　saturated　sodium　hydroxide　(NaOH).　The　effects　of　h-BN-OH　after　ultrasonic　dispersion　for　10　min,　20　min,　30　min　and　40　min　on　the　setting　time,　fluidity,　resistivity,　mascroscopic　strength　and　microscopic　Young＇s　modulus　of　hydration　products　of　ordinary　Portland　cement　were　investigated.　Fourier　transform　infrared　spectroscopy　(FTIR)　test　results　showed　that　h-BN-OH　had　obvious　hydroxyl　infrared　characteristic　peaks.　After　adding　h-BN-OH　into　cement　paste,　the　initial　and　final　setting　time　of　cement　paste　was　shortened　6.44-15.34%　and　5.05-13.00%,　respectively;　the　fluidity　was　reduced　9.86-22.79%,　and　the　resistivity　was　increased　7.14-25.96%.　Meanwhile,　the　compressive　strength　of　cement　paste　and　the　microscopic　Young＇s　modulus　of　hydration　products　were　significantly　improved　10.82-40.85%　and　9.90-31.01%,　respectively.　The　main　reasons　were　as　follows:　(1)　The　dispersion　effect　and　stability　of　h-BN-OH　in　cement　pore　solution　were　better　than　that　of　pristine　h-BN,　and　the　hydroxyl　group　grafted　on　the　h-BN-OH　provided　nucleation　sites　for　the　growth　of　calcium-silicate　hydrate　(C-S-H)　gel.　(2)　The　hydroxyl　groups　grafted　on　the　h-BN-OH　can　absorb　Ca2+,　resulting　the　polymerization　degree　(n(c))　and　medium　chain　length　(MCL)　of　C-S-H　gel　increased.　The　formation　of　C-S-H　gel　network　structure　was　accelerated　by　the　increasing　proportion　of　Q(3).　(3)　The　pore　structure　of　cement　hydration　products　was　significantly　optimized.