M-learning is short for mobile learning, that takes place with the help of mobile devices to access course materials everywhere and at anytime; In order to improve data transmission and storage of M-learning system, mobile database technology was introduced. Mobile devices' many features, such as mobility, disconnection, heterogeneity and distribution, etc, make traditional transaction processing schemes is no longer applicable to mobile computing environment. So a new mobile database model based on agent was proposed, and transaction processing process based on this model was set forth. The model can shield the heterogeneous among all members. And the model based on agent can effectively decompose long-lived transaction, as to complete query optimization of mobile database, and improve the efficiency of data processing in M-learning.