With concise analysis methods, the mathematical model of the flying shear kinematics and its operating program in the computer have been developed, which is specially used for analysing the synchronous cutting characteristics of crank rotating flying shear with the radial equal speed mechanism both in its adjusting or running station on line and in the design of a new shear.

From the relation of hydraulic characteristic of radial distributor,the author designs the transmission size of the guiding apparatus,so that the guide operation moment of the force is optimal,and the proportionate under the blades movement is ensured,which can be used as a reference for the structure design of radial distributors.