In order to help the telephone customer service agents provide uninterrupted and stable quality services, it is necessary to develop the intelligent phone number checking engine. Based on the research of the longest common subsequence algorithm and the longest common sub-element sequence algorithm, a short text similarity calculation algorithm is proposed to improve the accuracy of the search number. Based on this, the intelligent phone number checking engine and its implementation method are designed. Taking into account the actual needs, the data is preprocessed by word segmentation, abbreviation substitution, synonym replacement, and construction of stopword vocabularies in natural language processing; further data processing is accomplished by similar calculations based on HowNet and synonym word forests. Externally API interfaces abiding by REST-compliant are provided. Experiments show that the design of the intelligent phone number checking engine is feasible and has good business processing capabilities to meet user needs. At the same time, there are also some problems that need further improvement. The intelligent phone number checking engine can provide 24 hours uninterrupted service. Compared with manual services, it has higher search efficiency and more stable quality services, which can provide reference for the development of smart phone customer service.