We have studied a method of pretilting liquid crystal on the surface of a substrate by photoaligning the polyimide substrate containing azo type chromophores. The liquid crystal molecules were pretilted by inducing anisotropy in the cell substrate with anisotropic photopumping of the chromophores. Using the crystal rotation method, we have investigated the orientational ordering of 5CB liquid crystal on a photoaligned azo-polyimide substrate.