Compressive loading at knee during walking on slope can caused the initiation and progression of osteoarthritis due to cartilage degeneration impacted which may require long periods of medical treatment and costly. The purpose of this pilot study is to analyzed the effect of surface inclination to joint contact force at knee in frontal, sagittal and transverse plane during walking. The differences in joint contact forces obtained were analyzed using Freebody 2.0 software. The findings of this pilot study indicate that, both flat and inclined walking have almost similar trends of joint contact force at knee for each direction compared to decline walking. However, each walking condition show different magnitude of tibiofemoral joint contact force. In conclusion, the result of this pilot study could not be taken as a whole. Advancement on surface angle and number of subjects is as well as research in other joint of lower limb is recommended for future work to further understand and prevent any common injury risk during walking on inclined surface.