Abstract: A location based service method and location based service system is provided. The location based service method includes: making requests for position determination of a client terminal according to a first position determination method and a second position determination method, in response to a location based service request; receiving a position determination result according to the first position determination method, and generating first location data including additional information which corresponds to the position determination result according to the first position determination method; providing the client terminal with the first location data; receiving a position determination result according to the second position determination method, and generating second location data, the second location data being refined first location data; and providing the client terminal with the second location data.