A new method was presented to retrieve medical image, which is based on mut
ual information method. A database of ultrasonic images was retrieved by th
e method. The result shows that this method not only has the features of tr
anslation invarant, rotation invariant and scale invariant, but also avoids
image segmentation which may lead to a complex calculation. The method has
the advantage that the speed of retrieval will not get slow with the incre
ase of the number of images. This new method can also be used to retrieve s
imilar non-medical image.