Abstract: The performance characteristics and research status of CuInSe2 film and solar cells are briefly introduced. The emphasis is laid on several fundamental issues of CIS film solar cells, which importantly affect their large-scale application, including preparation of CIS films directly by RF-sputtering to avoid the selenization process, the possibility of replacement of CdS by ZnO as buffer layers, and the effect and internal mechanism of Na+ ion on properties of CIS films and solar cells. Such research is looking forward to promote the industrialization of CIS film solar cells.