This chapter explores Sociocultural Theory (SCT) and its significance in second language studies. It discusses the relationship between Vygotsky's Cultural-Historical Psychology (CHP) and Marxist logic of Dialectics and the application of CHP in SLA studies. The chapter also examines dynamic assessment research, including its application in L2 teaching and a scientometric analysis of DA research. Furthermore, it delves into teacher development research, analyzing the trajectory of teacher concept development and the relationship between teachers' beliefs, teaching practices, and teacher identity. These sections provide valuable insights into the theoretical connotations and empirical applications of Chinese SCT L2 studies.