Abstract: In consideration on the on-line R-value measurement of aluminum deep drawing sheets, the selection of initial slip systems was analyzed according to the activation process of the slip systems during plastic deformation. Initial R values of the 3104 aluminum sheet in different directions were calculated. It was shown that texture is the most important effect factor for determining R value, of which initial R value is the key part. The textures existing in the 3104 sheet decide that R₀ is the lowest and R₉₀ is the highest. The calculation indicates that the 111 fiber texture can increase the deep draw-ability drastically while the earring effect is obviously reduced.