In the service Internet environment, different requirements may be made simultaneously by different users. It is a great challenge to structure composite service quickly and effectively to fulfill personalized requirements.This paper presented a personalized service customization method based on patterns.The requirement patterns and service patterns from historical service request and service solutions were identified, and the matching relationship between the requirement patterns and service patterns were established. An algorithm called LPSC was proposed to deal with personalized requirements by which personalized requirements were classified according to the similarity between requirements and virtual requirements were constructed to replace them. Then each virtual requirement could be replaced by a limited number of requirement patterns.Through the matching relationship established between requirement patterns and service patterns,we could find optimal service pattern set that suited the requirement patterns. Finally, service solutions could be obtained by the composition of service patterns.Experimental results prove the effectiveness of the proposed algorithm.