As the fetus grows during pregnancy, the weight of pregnant women changes rapidly. Increased load on the knee joint due to such rapid weight gain and increased fluidity of the joint caused by the hormone put a great deal of strain on the knee joints of the pregnant women and cause the risk of injury. Therefore, in this paper, we investigated the correlation between the walking angle difference during walking and the moment on the knee of the pregnant woman, and tried to find a walking method suitable for prevention of knee joint injuries in pregnant women. The model was selected as the pregnant woman in the third trimester with the greatest weight gain of the pregnant women. We analyzed the difference of moment applied to the knee joint caused by the angle of foot opening angle at the moment when the foot was touched to the ground during walking.