Disclosed is a method for controlling the shapes of FM-AM mixed halftone dots on the multi-bit depth imaging apparatus. In the prior art, since the reproduction of the shapes of the dots in various gradations is absolutely based on the theory of random error diffusion and is influenced by the dynamic controlling output mechanism for the multi-bit dots, it is hard to assure the controllability of the shapes of the dots in a certain gradation. Based on the prior art, the dynamic statistic algorithm with adjacent output gray levels is introduced to assure the controllability of the shapes of the dots and solve the problem of random change of the shapes of the dots due to the randomicity of the error diffusion. According to the disclosed method, the features of the multi-bit imaging apparatus can be achieved fully in light of the requirements of the dots on the basis of the original method for multi-bit FM-AM mixed screening using error diffusion based on dual-feedback. The effect of FM-AM mixed halftone screening can be achieved under low resolution with controllable shapes of the dots. The problem of granular sensation can be solved during the practical output of the mixed halftone dots so as to assure the smooth effect of the gradations.