A　fluorometric　method　for　pyrophosphatase　(PPase)　activity　detection　was　developed　based　on　click　chemistry.　Cu(II)　can　coordinate　with　pyrophosphate　(PPi),　the　addition　of　pyrophosphatase　(PPase)　into　the　above　system　can　destroy　the　coordinate　compound　because　PPase　catalyzes　the　hydrolysis　of　PPi　into　inorganic　phosphate　and　produces　free　Cu(II),　and　free　Cu(II)　can　be　reduced　by　sodium　ascorbate　(SA)　to　form　Cu(I),　which　in　turn　initiates　the　ligating　reaction　between　nonfluorescent　3-azidocoumarins　and　terminal　alkynes　to　produce　a　highly　fluorescent　triazole　complex,　based　on　which,　a　simple　and　sensitive　turn　on　fluorometric　method　for　PPase　can　be　developed.　The　fluorescence　intensity　of　the　system　has　a　linear　relationship　with　the　logarithm　of　the　PPase　concentration　in　the　range　of　0.5　and　10　mU　with　a　detection　limit　down　to　0.2　mU　(S/N　=　3).　This　method　is　cost-effective　and　convenient　without　any　labels　or　complicated　operations.　The　proposed　system　was　applied　to　screen　the　potential　PPase　inhibitor　with　high　efficiency.　The　proposed　method　can　be　applied　to　diagnosis　of　PPase-related　diseases.