Abstract: Secondary electron emission (SEE) is a complicated process involving interaction between charged particles and solid surface. Due to advantages of high secondary electron yields (δ) and chemical stability, MgO thin films have broad applications in various photomultiplier tubes (PMT) and AC plasma display panels. The fundamental principles of SEE and the development of MgO thin films related SEE materials over the last several decades were reviewed in this paper. Based on literature review and previous research work in our group, the development of MgO and doped MgO thin films with high δ was presented. Finally, requirements and prospects for SEE materials nowadays were summarized.