As an essential mechanism of group collaboration in software development, code comments are widely used by developers to improve the efficiency of specific developing tasks. However, code comments do not directly affect the software operation, and developers often ignore them, which leads to poor quality of code comments and affects development efficiency. Quality issues of code comments hinder code understanding, bring misunderstanding, or even introduce bugs, which receive widespread attention from researchers. This study systematically analyzes the research work of global scholars on quality issues of code comments in recent years by literature review. It also summarizes related studies in three aspects: evaluation dimensions of code comment quality, indicators of code comment quality, and strategies to promote code comment quality and points out shortcomings, challenges, and suggestions for the current research.