为了厘清共享单车参与各方的权利与义务，更好地发挥市场调节作用，提高资源配置效 率，从共享单车的经济外部性特征入手，运用经济学成本收益理论分析了共享单车的负外部性产 生的原因，论证了共享单车外部成本管理的必要性，最后从外部成本内部化角度，面向政府、企 业和用户分别提出了管理策略，为共享单车的可持续发展提供参考。研究结果表明，共享单车的 正外部性主要体现在促进自行车出行，优化交通结构，促进交通领域节能减排；负外部性主要体 现在挤占道路资源，车辆乱停乱放，安全隐患突出；消减共享单车负外部性的根本手段是控制共 享单车的规模在动态最优投放量附近。在市场价格调节机制失灵的情况下，必须发挥政府的激励 作用，将可持续发展目标、共享单车企业、共享单车使用者紧密联系起来，共同消减共享单车带 来的负外部成本。

In order to clarify the rights and duties of bike-sharing participants, strengthen the market function, and improve the efficiency of resource allocation, the causes of negative externalities of bikesharing were analyzed by using cost-benefit theory and the necessity of the external cost management of bike-sharing was demonstrated based on economic exterality characteristic of bike-sharing. Finally, from the perspective of internalization of external costs, some management strategies were proposed for the government, enterprises and users to provide references for sustainable development of bike-sharing. The research results show that the positive externalities of bike-sharing are mainly to promote bicycle travel, optimize traffic structure, promote energy-saving and emission-reduction; the negative externali⁃ ties of bike-sharing are mainly excessive occupy road resources, parking bike at will, and safety hazards prominent. The fundamental way to reduce the negative externalities of bike-sharing is to control the scale near the dynamic optimal allocation. In the absence of market price adjustment mechanism, the relation among the goal of sustainable development, enterprises and users should be strengthened to reduce the external costs by playing the government′s incentive role.