The invention provides a method for safety monitoring of website legality. The method for safety monitoring of website legality comprises the following steps: collecting the interaction data traffic between a user and a website at the exit of the internet data center; analyzing traffic data and obtaining the domain name address of the website in a data packet; matching the domain name address of the website with website domain names stored in a domain name filing library, if the match fails, determining the website to be an illegal website, and sending a blocking packet or redirection packet to the user to prevent the user from accessing, and if the match is successful, determining the website to be a filing website and restoring the text content of the data packet; and matching the restored text content with an illegal keyword library, if the match is successful, determining the website to be an illegal website, and sending the blocking packet or redirection packet to the user to prevent the user from accessing. According to the invention, by means of the bypass redirection technology, the legality of the website domain name and the legality of the content of the website are recognized automatically to prevent the user from accessing the illegal website and provide a friendly prompting page for the user.