OBJECTIVE： To investigate clinical efficacy and safety of different dosages of bromocriptine in the treatment prolactinoma， and its effects on serum prolactin （PRL） and tumor volume. METHODS： A total of 60 patients with prolactinoma were selected from our hospital during Jan.-Dec. 2015 as research objects， and then divided into group A and B according to random number table， with 30 cases in each group. Both groups were given Bromocriptine mesilate tablets orally during meal. Group A was given medicine with initial dose of 2.5 mg/d， increasing to 3.75 mg/d 3 d later， increasing by 2.5 mg every week after 2-3 d， and then recovering to 3.75 mg/d till serum PRL level had been controlled. Group B was given medicine with initial dose of 1.25 mg/d， increasing to 2.5 mg/d 3 d later， increasing by 1.25-2.5 mg every week after 2-3 d， and then recovering to 2.5 mg/d till serum PRL level recovered to normal. Both groups were treated for consecutive 3 months. Clinical efficacies as well as serum level of PRL and tumor size were observed in 2 groups， and the occurrence of ADR was recorded. RESULTS： The total response rate of group A （83.33％） was higher than that of group B （66.67％）， without statistical significance （P＞0.05）. Before treatment， there was no statistical significance in serum level of PRL and tumor size between 2 groups （P＞0.05）. After 1， 2 months of treatment， serum levels of PRL in 2 groups were decreased significantly， and the group A was significantly lower than the group B， with statistical significance （P＜0.05）. After 3 months of treatment， serum levels of PRL in 2 groups were decreased significantly compared to before treatment， but there was no statistical significance between 2 groups （P＞0.05）. After treatment， tumor size of 2 groups were decreased significantly， and large adenoma and giant adenoma size in group A were significantly smaller than group B， with statistical significance （P＜0.05）. There was no statistical significance in microadenoma size between group A and B （P＞0.05）. The incidence of ADR in group A （12 cases， 40.00％） was significantly higher than group B （5 cases， 16.67％）， with statistical significance （P＜0.05）. CONCLUSIONS： Increasing dosages of bromocriptine no significant influence on therapeutic effect of prolactinoma，but it can shorten the time of serum PRL level back to normal， and reduce the tumor size. The incidence of adverse reactions increase with the dosage.