For obtaining size parameter of Ti-6Al-4V forging lug quickly and obtaining suitable load efficiency factor, based on 3 load efficiency factors about the lug with related literature and general calculated formula ,3 associated parameters are united into 1 associated parameter ,that is a ratio of b (the minimum radial section width of lug)to D( the lug inner diameter). And 3 new curves are drew up. By using 3 curves of this paper ,The relationship between the size parameter of b/ D of lug and load efficiency factor can be obtained quickly and effectively. So we can achieve our purpose of fast designing a fitting lug.