In the era of “Internet+”, data is the most valuable resource of the Internet. Attackers often use SQL injection attacks to destroy the database in order to obtain important data information in the database. The threat to database security is becoming more and more serious. At present, the research on SQL injection attacks mostly focuses on traditional SQL injection attacks, but lacks the cognition of new advanced SQL injection technology with stronger concealment and higher risk, and the research on related detection and defense technology. In response to this phenomenon, this paper analyzes and evaluates traditional and advanced SQL injection attack technologies and their technical characteristics based on the classification of SQL injection technologies; summarizes existing detection and defense technologies, and evaluates the advantages and disadvantages of these methods for defense effectiveness; finally The problems existing in the current research field are sorted out, and suggestions for future research directions are put forward.