Abstract: The optimal design of the combined structure of nozzle conic support and case joint is completed by means of a mixed method of optimality criterion method and mathematic programming method.A valuable method and helpful conclusions are supplied for decreasing structural mass and optimizing shape of nozzle support.Calculation of practical examples shows that the multi conic support is better than single conic one especially a short shell near the flang is approximate to cylindrical shell which can decrease the stress peak efficiently.The thicknesses of the shells and the flange,the thickness and the width of the case joint are dereased magnificently,therefore the overal mass of the structure is cut down by 16.35%.