Abstract: The variation of dynamic stress of spring plates in the ledger unit in ZJ116 cigarette maker was investigated. Elastic modulus, Poisson ratio and density of the spring plate were tested via tensile test, and the calculation model for ledger unit was established based on the test results and rigid-flexible coupling theory. The dynamic stress of the spring plate in the process of cigarette cutting was calculated with the established model, the results showed that:1) Elastic modulus of the spring plate was 94.140 4 GPa with Poisson ratio of 0.296 7 and density of 1 599.69 kg/m³. 2) In the process of cigarette cutting, the dynamic stress of spring plate increased from its center to both ends, and the two ends, which connected with bracket and ledger separately, of spring plate tended to crack even break, which was consistent with the result of fatigue test.