Objective: To assess the safety and effectiveness of cantharidin in treating pediatric molluscum contagiosum (MC). Methods: A total of 45 patients were enrolled in our study and randomized to divided into a control group and a treatment group. A 2-week treatment was performed: stage one for 1 week, the control group was given normal saline, the treatment group was given cantharidin; stage two for 1 week, both groups received cantharidin treatment. The number of lesions was calculated at 0, 1, 2 weeks of the treatment, and the adverse reactions were recorded. Results: There is no statistically significant in gender, age, prior treatment, lesion count before the treatment (P>0.05). In stage one, there is no statistically significant difference between 0th week and 1st week in the control group (P=0.866). The number of lesions of 1st week in the treatment group was lower than that in the control group, the difference was statistically significant (P=0.032). At the same time, the number of lesions in the treatment group was lower than that in the 0th week, the difference was statistically significant (P=0.006). In the second-stage treatment, the number of skin lesions in the control group in 2nd week was lower than the 0th weeks, the difference was statistically significant (P=0.045). The number of lesions after treatment in 2nd week in the treatment group was lower than the number of lesions at the 2nd week of the control group, the difference was statistically significant (P=0.008). At the same time, the number of lesions in the treatment group at the 2nd week was also lower than that in the same group at the 0th week. The difference was statistically significant (P=0.010). No serious adverse events were observed. Conclusion: Cantharidin is effective for treating MC in children, and the treatment is safe and worthy of clinical promotion.