Due to the complex environment in urban area, the ground surface dewatering for Metro stations constructed by PBA method becomes more and more difficult. As a result, it is necessary to study the underground dewatering technology. According to the conventional underground dewatering technology, a separate dewatering heading is installed outside the main structure of the Metro station, which has such disadvantages as huge abandoned works, high cost and serious influence on the environment. In this paper, comparison and contrast is made among several underground dewatering schemes, with the dewatering of Wangfujing station on No. 8 line of Beijing Metro as an example. An innovative underground dewatering method for Metro stations constructed by PBA method, i.e., enlarging or combining the upper headings of the Metro station to provide space for underground dewatering, is proposed on basis of studying on the characteristics of PBA method. In the end, the problem of underground dewatering for Metro stations constructed by PBA method has been successfully solved. The authors also suggest that proper schemes of dewatering in headings should be selected according to the structure types and hydrological conditions of the Metro station. 