Forming accuracy is one of the important indicators to evaluate the forming quality of a tubular part by tube hydroforming. However, shape asymmetry on cross-section of tubular part produced by hydroforming with radial crushing (THFRC) inevitably appears due to the friction between the die and the part. In this paper, a circular tube is formed into a square cross-section one by THFRC under the various loading paths and the influence of friction on the forming accuracy of cross-section of the bulged parts is analyzed by using numerical simulation. The results show that the larger the tube is expended to, the lower the forming accuracy is under the identical coefficients of friction (COF); the larger the COF value is, the lower the forming accuracy is under a constant maximum hydraulic pressure. In a word, a reasonable loading path and a low COF value can observably improve the forming accuracy of the bulged tube.