Objective   To discuss diagnostic indexes of rickets for infant and toddler and its significance. Methods  Bone alkaline phosphatase (BALP)was tested in 83 cases of children aged 0 to 3 with a history of vitamin D dificiency and nonspecific symptoms of rickets. Those whose BALP were more than 250-U·L    -1 with changes of bones were given Yingkangli containing vitamin D 300-000-IU, and their BALP was tested one month later. Results  The younger the patients, the higher the positive rate of BALP. There was a significant relation between positive BALP and the changes of bones.The index of BALP positive was more sensitive than changes of bones,such as rib ectropion (41.2%) and enlarged quadrangular fonticulus (26.5%). Those infants and toddlers with the changes of bones had dramatically effect when treated with vitamin D.Conclusion  The history of the lacking of vitamin D, the nonspecific symptoms of rickets, and positive BALP can be taken as the simple diagnostic indexes of rickets for infants and toddlers. The changes,either first or secondary manifestion of bones is an indicator of active rickets.