This article mainly presents the design and relevant calculation of the hydraulic system the master arm, vice-moves the arm, expands and contracts the arm size parameter in the formation devices. First of all, design goal and design basis Serviceability And so on The key point is the work survey and the performance parameter design calculation and designs the request and how to choose the major components according to the parameters If the hydraulic cylinder, sells the axis and so Secondly, the article presents the working principle of every part in the design how the bucket, the arm and the boom斗Throwout lever respectively works. A After that, it reveals the design of the drive of the working settings including the design of the major parameters of the hydraulic cylinder and it alculation at work,If hydraulic pump, electrical machinery shaping design and computation In the end, Carries on the design and the computation to the multi-purpose scoop size parameter Then every phases of Working device design is studied on ,and with design software modelling to the smooth installment master arm, vice-moves the arm, the expansion and contraction moves the arm the stress analysis, the movement simulation, the parameter optimizes, intensity examination and so on.