The scattering phenomenon has an important influence on the reconstructed image in Cone Beam CT (CBCT) imaging systems, and is a long-lasting research topic on CBCT. Focusing on the scatter artifact in the cone beam CT system, we proposed a new scatter correction method that needed to add a beam attenuation grid (BAG) between the X - ray source and the tested object. This study educed the scatter correction algorithm based on the Beer theorem. Through subtracting the scatter distribution image from the original projection image, we can acquire the scatter-corrected projection Images of the tested object. The method has been verified by preliminary experimental results on phantom. The result showed that the method can effectively reduce the scatter artifacts, increase the image contrast and increase the quality of the reconstructed slice image. This method is computationally efficient and easy to implement without the loss of real-time imaging capabilities.