Abstract: An upper bound model for ironing is proposed according to the upper bound theorem. Two independent parameters are used to optimize the upper bound approach in this model. Through calculation, the analytical results agree well with the experimental results. Meanwhile, based on the proposed model, the influence on the ironing force has been analysed of main technological parameters such as the ironing rate, semicone angle, the ratio of inside radius to outside radius, the lenghth of the working land of the die and friction factors existing between the billet and die.