Objective To analyze the quantitative factors influencing the curative effect in 131I treatment of hyperthyroidism. Methods The quantitative factors in hyperthyroidism patients with 131I treatment including patients’ thyroid mass, thyroid iodine uptake rates, prevalence of age, the prevalence of gender, illness course and anti-thyroid drugs (ATD) on the curative effect of 131I treatment and early hypothyroidism (EH) were analyzed to conduct a statistical analysis. Results In all the 131I treated patients, no matter male or female, the first 131I treatment or second treatment, there were no significantly difference on cure rates and incidence of EH (P> 0.05). The cure rate and EH rate in patients with thyroid mass 20-30g were significantly higher than those with 31～80 g（P＜0.01）. There were no significantly difference on cure rates and EH rates among the patients with thyroid mass from 31 to 80 g and 24h thyroid iodine uptake from 45% to 95% (P＞0.05）. The EH rates in patients between the age of 16 to 20 years were significantly higher than that of 21 to 66 years group（P＜0.05）, which showed that the thyroid of patients younger than 20 years old were more susceptible to radiation damage. The cure rates of patients with illness course less than 6 months were significantly higher than those longer than half year（P＜0.05）, but the difference of the EH rates were not statistically significant regardless of illness course（P＞0.05）. The cure rates and EH rates, before and after ATD treatment with different drugs, were significantly different （P＜0.01）. Conclusion The quantitative factors influencing the curative effect in 131I treatment of hyperthyroidism should be analyzed carefully and they might have important clinical significance in the hyperthyroidism patients with 131I treatment.