Abstract: The prospect of microwave integrated circuits(MIC) on silicon(Si) substrates is very attracting.In this paper the advantages of Si used as the substrate of MIC are reviewed.Electrical performance of microwave transmission lines and passive elements on Si,and of SiGe HBT are analyzed.The research progress of MIC on Si is briefly presented and some discussions are given for the uniqueness and application of integrating digital circuits with RF and microwave circuits on Si substrates.