In recent years, major progress has been obtained in studying the early events in TCR-mediated signaling. c-Cb1 has been found to be a negative regulatory factor of the tyrosine kinases in ZAP-70/SyK family. The studies on LAT, SLP-76, ItK and Vav have shown their roles in the signal transduction of Ras and phospholipase Cx1 to Ca2+. Micro-glycolipid raft also plays important role in T cell activation. This minireview shows a brief introduction to the process of TCR-mediated signaling.