Abstract: 　Objectives　To explore the efficacy of CaNa2EDTA in the treatment of chronic moderate lead poisoning, so as to optimize the chelation therapy for lead poisoning in children. Methods　The clinical data of 14 patients with chronic moderate lead poisoning treated with CaNa2EDTA for 3 consecutive courses of lead removal during September 2014 to December 2016 were analyzed retrospectively. Twenty-four hour urinary lead levels during hospitalization were analyzed. The changes of blood lead levels before treatment, 3 days, and 5 days after treatment were also analyzed. Results　In the 14 children (4 males and 10 females) average age was 2.35±1.47 years. After treatment with CaNa2EDTA for 3 consecutive courses, the blood lead levels were decreased significantly in all the patients, and the blood lead levels at 3 days after treatment were 0.76, 0.77, 0.72 times those at 5 days after treatment respectively. The decrease of blood lead levels per unit of drug in the first 3 days of treatment were significantly higher than those in 5 days of treatment (P<0.05). The decrease of blood lead levels at 3 days after treatment was 0.65, 0.71, 0.70 times , those in 5 days’ treatment respectively. The decrease of urine lead levels per unit of drug in the first 3 days of treatment were significantly higher than those in 5 days of treatment (P<0.05). Conclusions　CaNa2EDTA has an obvious effect on removal of lead.The efficiency of lead removal in 3 days of treatment was higher than in 5 days of treatment. Thus, a course of treatment for 3 days may be an altenative for a course of 5 days.