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 references for the full implementation of medical electronic bills. Methods: Based on Technology Acceptance Model(TAM), Theory of Planned Behavior(TPB) and Diffusion of Innovations Theory(IDT), decision model of outpatient medical electronic bill is established to conduct the path analysis. Results: The adoption intention of users is positively affected by use attitude and subjective norms. Perceived ease of use has a positive effect on users' use attitude through direct and indirect impact. Complexity and relative advantage significantly affect user perception. 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.