The invention discloses a 
medical safety tracing method and 
system based on a block chain. The method includes the following steps: S1, medical data is saved to a main node of a block chain; S2, medical institutions collect medical data during 
medical treatment; S3, experts and doctors make medical plans according to the medical data and sign the medical plans, and the 
record is saved to the 
blockchain and broadcasted; S4, the state of illness is judged; if the illness is mild, a patient gets medicines and then goes to the nurse 
station for transfusion to complete treatment; or, 
surgical treatment is arranged, preoperative 
physical examination is carried out, the result is saved to the block chain, and the method goes to S5; S5, 
surgical treatment is carried out, and the signature data during operation is saved to the block chain; S6, 
after treatment is completed, the medication and 
vital signs of the patient are recorded regularly, saved to the block chain and updated in real time; and S7, after the patient is discharged from the hospital, the daily medication of the patient is recorded in real time and saved to the block chain. The method and the 
system have the 
advantage that:through the information 
anonymity and decentralization of the block chain technology, medical institutions can obtain medical data through private keys under the permission of patients to achieve 
information sharing.