A web service registering system with service evaluation and utility knowledge is disclosed. The system includes a service interface, a database, a UDDI service register machine and a core integrating module. A service user can generate a function calling message corresponding to a target service of a service provider via the service interface. A service evaluation and a utility knowledge corresponding to the target service are stored in the database. The web service registering system generates integration information by integrating the service evaluation, the utility knowledge, and the target service via the core integrating module according the function calling message and connecting the function service of the UDDI service register machine. Then, the web service registering system shows the integration information on the service interface.