With the rapid development of wireless communications systems, different system standards are being merged. Operators take stringent measures to reduce Operational Expenditure (OPEX) and Capital Expenditure (CAPEX); and as a result, soft base stations supporting multiple standards become the evolutionary tend of wireless base stations. This paper introduces the background of soft base stations and analyzes their architecture design, system modules. The key technologies in system implementation and future directions are also presented. With the rapid development of wireless communications systems, different system standards are being merged. Operators take stringent measures to reduce Operational Expenditure (OPEX) and Capital Expenditure (CAPEX); and as a result, soft base stations supporting multiple standards become the evolutionary tend of of This paper introduces the background of soft base stations and analyzes their architecture design, system modules. The key technologies in system implementation and future directions are also presented.