Abstract: A cylindrical coordinate velocity field for round bar and wire drawing was established. A new integration method of strain rate inner-product was proposed, and then an analytical solution was obtained. The effects of friction factor on optimal die angle and stress state coefficient were also discussed. The results showed that the optimal die angel αopt and stress state coefficient nσ increase with the m increasing, the nσ obtains its minimum value at αopt. In order to validate the accuracy of the calculated result, it is compared with that of Avitzur. It showed that the proposed solution obtained by the inner-product method is in good agreement with Avitzur solution. Besides, the effect of friction factor on the limit deformation ratio is also discussed.