The similarity mapping plays an important role in the medical image processing field, including signal investigation, image segmentation and pharmacokinetics of local tissues. Based on tissue similarity mapping (TSM), the concept of dynamic imaging was generalized in this paper, and an improved method was proposed. By the new method, the application fields of TSM can be extended and the image quality can be enhanced dramatically. With 16 series of human brain images acquired from 12-echo T2 * weighted magnetic resonance imaging, these experiments validate that the signal to noise ratio (SNR) from improved method is increased by 3.8 to 17.4 times.