The main reason of reduction walking ability is muscle weakness of the psoas major. But muscular strength of the psoas major judged from cross sectional area in the previous researches. In this paper, we analyzed quantitatively muscles around the hip joint for extension and flexion movement of knee joint by using angular momentum. We think that angular momentum expresses the intensity of muscle exercise. First, we used the 3D lower limbs musculoskeletal model of SCOT L. DELP. And, we estimated muscle activation of muscles around hip joint by using the 3D loer limbs musculoskeletal model. 3D lower limbs musculoskeletal model used Hill type model which F.E.Zajac suggested. Next, the muscle torque was calculated from muscle activation of muscles around the hip joint. Finally, the angular momentum was calculated from the muscle torque around the hip joint. And, the driving power was calcuated from driving torque of the hip joint. As those results, the angular momentum of psoas major was about 1.5-4 times bigger than other muscles. Therefore, we could confirm that the muscle force of psoas major is important for extension and flexion movement of knee joint. Namely, we could confirm quantitatively that psoas major is the most important to the hip joint movement in muscles around the hip joint.