Objectives To improve the detection of bone alkaline phosphatase(BAP) for early diagnosis and prevention of rickets for reducing missed diagnosis and misdiagnosis. Methods Enzyme-linked immuno sorbent assay (ELISA) method was used to detect of BAP of rickets,suspected rickets and healthy infants quantitatively.The reference range was established to find the critical point of diagnosis and evaluated its diagnostic value using ROC curve analysis.Further more,the diagnostic performance of quantitative BAP was compared with qualitative BAP and ALP. Results The reference range of ELISA quantitative detection of infant BAP was 68~246 U/L.With more than 280 U/L as threshold value of rickets,the diagnostic specificity was 99.6%,the sensitivity was 91.2%,the accuracy percentage was 98.2%,and positive likelihood ratio was 227.9.By contrast,with more than 236 U/L quantitative ALP as the thershold value of rickets,the diagnostic specificity was 72.0%,the sensitivity was 79.4%,the accuracy percentage was 72.9%,and positive likelihood ratio was 2.8.The specificity of BAP qualitative to diagnosis of rickets was 84.8%,the sensitivity was 35.3%,the accuracy percentage was 78.9% and positive likelihood ratio was 2.3.For 23 cases with early signs of rickets,BAP ELISA quantitative hinted rickets in 16 cases (69.6%),BAP qualitative hinted rickets in 6 cases (26.1%),ALP quantitative hinted rickets in 11 cases (47.8%). Conclusions Compared with ALP quantitative and BAP qualitative,BAP quantitative with ELISA showed a better diagnostic capability of infant rickets.BAP ELISA can earlier find the change of the serum marker in infant with rickets,facilitate timely intervention.Therefore,it is recommended that detecting BAP with ELISA quantitative to reduce missed diagnosis and misdiagnosis of rickets.