Objective：To explore the main factors affecting the use of medical electronic bills under the background of medical and health system reform, so as to provide reference for the full implementation of medical electronic bills. Methods: Based on TAM, TPB and DIT, decision model of outpatient medical electronic bill is established to analysis. Results: The adoption intention of users is positively affected by use attitude and subjective norms. Perceived usefulness and perceived ease of use take attitude toward using as the intermediary variable, which has an indirect impact on adoption intention. Complexity and relative advantage indirectly affect users" using behavior. Conclusion: In order to promote the sustainable development of medical electronic bills, hospitals should establish and improve the electronic bill management system, unify the cost data collection standards, highlight the functions and build a diversified coordination mechanism.