Tudging from the Principle of the work done by the exciting force of the nozzles, the present paper describes the inclinic placement of the nozzles for decreasing the dynamic stresses of the first tone's vibration modes. An accident stage of the medium pressure rotor of the steam turbine produced in this country is calculated as an example. The calculating result indicates that the dynamic stresses of all the first tone's vibration modes can be remarkably reduced. In the dangerous tangential bending Bo modes, it decreases more than 50%.