Abstract: ObjectiveTo evaluate the effects of prophylactic cranial irradiation( PCI) on the survival and brain metastatic rates in patients with limited small-cell lung cancer( SCLC) after complete remission. Methods: Fourty-nine patients with limited SCLC after complete remission treated with chemoradiotherapy were randomly divided into PCI group( 25 cases) and control group( 24 cases) .The PCI group were irradiated at the dose of 25 Gy; the control group didn't receive PCI.The rate of brain metastases and the 1，3，5-year survival rates were assessed.Results: The incidence of brain metastasis of PCI group and control were 12.0% and 41.7%，respectively， the difference of which was statistically significant( P 0.05) .The 1，3 and 5 years survival rates in PCI group were 76.0%， 32.0% and 20.0%，respectively.The 1，3 and 5 years survival rates in control were 58.3%，20.8% and 12.5%，respectively.The differences of survival rates between two groups were not statistically significant( P 0.05) . Conclusions: PCI can decrease the incidence of brain metastasis of patients with limited SCLC.