Objective: To compare the efficacy and safety of 2 low-dose rituximab regimens in the treatment of children with primary immune thrombocytopenia (ITP). Methods: A total of 90 ITP children admitted to the Hematology Oncology Center of Beijing Children's Hospital from January 2018 to March 2021 were enrolled in this prospective cohort study. In the single-dose group, rituximab was given with a single dose of 375 mg/m2 (maximum dose 600 mg). In the 4-dose group, rituximab was given with a dose of 100 mg weekly (if body weight of the patient ≥ 30 kg, increase dosage to 200 mg weekly) for 4 weeks. Wilcoxon Mann-Whitney test, Chi-square test and Fisher's exact test were used to analyze the difference in efficacy, safety and treatment burden between two groups. Results: Among the 90 children, 41 were male and 49 were female, and the age of medication was 6.8 (4.1,10.0) years. There were 27 cases in the single-dose group and 63 cases in the 4-dose group.There were no significant differences in overall response rate, complete response rate and partial response rate between the single-dose group and 4-dose group (41% (11/27) vs. 33% (21/63), 26% (7/27) vs. 19% (12/63), 15% (4/27) vs. 14%(9/63), χ2=0.45, 0.54, 0.00, all P>0.05). The single-dose group was earlier to get overall response than the 4-dose group (1 (1, 1) vs. 3 (2, 6) weeks, Z=-3.24, P=0.001). There were no significant differences in the sustained response rate, the overall response rate in 1 year, the complete response rate in 1 year, and the partial response rate in 1 year between the single-dose group and the 4-dose group (33% (9/27) vs. 30% (19/63), 30% (8/27) vs. 24% (15/63), 19% (5/27) vs. 14% (9/63), 11% (3/27) vs. 10% (6/63), χ2=0.09, 0.34, 0.04, 0.00, all P>0.05). There were no significant differences in the duration of overall response, recurrence rate within half a year and one year, recurrence time and rate of adverse events between the single-dose group and 4-dose group (all P>0.05). The number of hospitalizations, the duration of hospital stays and the dosage of the single-dose group were significantly lower than those of the 4-dose group (1 (1, 1) vs. 4 (4, 4) times, 5 (4, 7) vs. 8 (5, 8) d, 400 (250, 500) vs. 400 (400, 800) mg, Z=-8.67, -3.03, -4.05, all P<0.05). Conclusions: The single-dose rituximab regimen is comparable to 4-dose rituximab regimen in effectiveness and safety for treatment of children ITP, but more economical and convenient. The single-dose rituximab regimen is more suitable for the second-line treatment of children ITP.