The invention provides a Naive Bayesian classification based mobile phone spam short message filtering method and system. The system comprises a message intercepting module, a cache, a blacklist filtering module, a keyword filtering module and an intelligent Naive Bayesian classification filtering module. The message intercepting module is used for intercepting newly received short messages; the blacklist filtering module is used for filtering the new short messages according to a preset blacklist; the keyword filtering module is used for filtering the new short messages on the basis of preset keyword pairs; the intelligent Naive Bayesian classification filtering module is used for calculating probability that whether the new short messages are spam short messages or not by adopting a Naive Bayesian algorithm on the basis of a pre-trained feature word bank, and judging the new short messages as the spam short messages if the probability ratio exceeds a preset threshold, and as normal short messages otherwise. By the Naive Bayesian classification based mobile phone spam short message filtering method and system, through combination of the blacklist, the keywords, Naive Bayesian classification technology and Chinese word segmentation technology, the short messages are judged whether to be the spam short messages or not intelligently, so that the spam short messages are filtered.