OBJECTIVE： To provide reference for reducing the harm of expired drugs to public health， improving the technical level of drug recovery， and realizing the green recycling economy of drugs. METHODS： The literatures analysis and field investigation is conducted to analyze the development status and the main problems in the construction of the reverse supply chain of expired drugs. According to the technical characteristics of block chain， the feasibility of building the reverse supply chain of expired drugs is analyzed. In order to verify the feasibility of the application of block chain technology in the construction of the expired drug reverse supply chain， this paper attempts to build the expired drug reverse supply chain from the perspective of block chain， and uses the system dynamics method to build a simulation model for each participant in the drug reverse supply chain and its operationing efficiency. RESULTS & CONCLUSIONS： The reverse supply chain of expired drugs constructed by the block chain technology could effectively solve the main problems of the reverse supply chain of expired drugs in China， such as many levels of participants， high logistics cost， low level of information. The simulation results showed when using block chain technology， the recovery efficiency and recovery quantity of each participant in the supply chain were significantly increased. The recovery efficiency of consumers and retailers increased from 20％ to 83％， and those of distributors and manufacturers increased from 40％ and 50％ to 83％， respectively. The recovery quantity of each participant also increased significantly with the increase of recovery efficiency. In the actual construction of the reverse supply chain of expired drugs， the enterprises involved in the drug supply chain should be taken as the leading role， and the multi-party participation of government agencies， industry platforms and consumers should be emphasized. Drug supply chain participating enterprises should use block chain technology to strengthen information communication between enterprises， establish an efficient information platform， and promote and guide consumers to actively participate in the construction of the reverse supply chain of expired drugs. The government should give full play to the guiding role of policy and strengthen the policy guarantee； the industry platform should learn from international advanced cases to form industry standards for the recovery process of expired drugs； consumers should fully understand the hazards of expired drugs and actively participate in the recovery of expired drugs.