With the development of web technology, spreading of Trojan and viruses via website vulnerabilities is becoming increasingly common. To solve this problem, we propose a system for malicious links detection based on security relevance of webpage script text and present the design and implementation of this system. Firstly, according to the current analysis of malicious links, we describe requirements and the general design for detection system. Secondly we describe the security-related algorithm with mathematical language, and give the data structure of this algorithm. Finally, we analyze and summarize the experimental results, and verify the reliability and rationality of system.