A numerical study was carried out using the finite element analysis program FINAL to investigate the effect of joint attributes on the maximum bending moment induced in the segmental tunnel lining, the analysis has been performed with different combination of segments number, joint orientation, tunnel depth, and the ground coefficient at rest ko. The model used in the analysis was for a water tunnel exposed to an internal and external water pressure, The results show that, the orientation of hinges has a significant effect on the moment induced in the lining in case of number of segments equals four, and it has a maximum value if the angle between the vertical axis of tunnel and the first joint is 45o, in this case it is preferable to erect the segments by keeping the angle between the axis of the tunnel and the first joint not more than 20o for the economic design. Also the orientation of joints on the moment of the lining decreases when the number of segments is five, and it is nearly no effect for the orientation if the number of segments is seven, or more. The number of joints has a greater effect on the maximum bending moment induced in the lining, where as the number of segments increases the bending moment decreases. However, beyond a number of joints equals ten the increase of number of joints has a little influence on the values of stresses induced in the lining, and for the economical design, the number of segments is preferred to be more than four, and the most economical design can be obtained if the number of joints is seven. For the effect of ko on the moment induced in the lining it was found that, the moment is nearly zero if ko equals 1.0, however the value of moment increases in the both cases, if Ko increases or decreases than 1.0.