The invention provides an online service system, which comprises at least two user databases, an interface unit, a database dynamic execution unit, and a common logic unit, wherein each user database comprises a system table, a system field table and a service function table; the interface unit is used for receiving input information of a user; the database dynamic execution unit is used for analyzing the table structure of the user database, dynamically generating corresponding execute statements according to the input information of the user, completing corresponding execution operation aiming at a corresponding datasheet in the user database and obtaining an individualized database aiming at the user; and the common logic unit is used for calling corresponding user databases of various users aiming at the users, executing common logic, and providing the online individualized service for the user. The system can quickly adjust the prior product functions or develop new product functions to make a software system fully meet the individualized requirements of different users, and simultaneously can be continuously expanded and improved according to the development of user service to meet the continuously developed informatization requirement of the users.