The present application relates to a liquid crystal aligning agent, a liquid crystal alignment film and a method for producing the same, as well as a liquid crystal display device. The liquid crystal aligning agent comprises (i) a first polyamic acid having a photoreactive group without a liquid crystal group; (ii) a second polyamic acid having a liquid crystal group without a photoreactive group; (iii) a third polyamic acid having both a liquid crystal group and a photoreactive group; (iv) a fourth polyamic acid having neither a photoreactive group nor a liquid crystal group. The liquid crystal display device using the liquid crystal alignment film formed by the liquid crystal aligning agent provided by the present disclosure has a high display contrast and an improved AC residual image.