In this article, a novel scatter correction approach was proposed based on the Klein-Nishina formulation. Through a series of deductions from this formulation, a principle was proposed that the photon intensity distribution was determined by the attenuation coefficient and the path length l. This means if 2 pencil beams pass through 2 objects with the same l, even if the attenuation coefficient and the path length l of the objects are different, they will still achieve the same photon intensity distribution, that is, the same point spread function. Subsequently, a novel scatter correction approach was established after a series of deductions based on this principle. The simulations and experiments demonstrated the correctness of our principle and the comparable correction effect of our scatter correction approach compared with the beam stop array method. Furthermore, because of the character of our method, the program has very high parallel computing features, which can dramatically increase the computation speed.