In recent years, digital signal modulation recognition has gradually become an important line of research in the field of wireless communication owing to its high information confidentiality and anti-noise ability. As one of the important features of modulation recognition, the constellation diagram has obvious advantages in feature extraction because it does not need to receive prior information on the signal during feature extraction. For the above reasons, this study presents an overview of digital signal modulation methods based on the constellation diagram. In particular, it starts by analyzing the basic principle of the constellation diagram. Then, the characteristics of the constellation diagram in various lines of research are analyzed by summarizing the existing digital signal modulation recognition schemes based on the constellation diagram. Finally, the development trend and future expectations of digital modulation recognition schemes based on the constellation diagram are presented.