URL lookup method for URL filtering system

The invention relates to the technical field of network information security, in particular to a uniform resource locater (URL) lookup method. The invention combines a hash method and a multi-string matching method in the prior URL lookup method and provides a URL lookup method well meeting the requirements of performance and functions of a URL filtering system. Compared with the prior lookup method, the URL lookup method for the URL filtering system is quick in lookup, stable in performance and high in storage rate, can meet the storage requirements of a constantly increasing URL blacklist and supports premix matching. The URL lookup method is applicable to the URL filtering system, can realize the effective control of online behaviors of users conveniently and can also be used in other network applications such as search engine, web cache and layer-7 switching.