The classic bowtie filter for CT is used to shape an xray beam and equalize its flux reaching different detector channels. An ideal bowtie filter, dynamic bowtie, could dynamically modulate incoming xray beams with CT scanning as a function of the angle of the xray with respect to a patient to balance the photon flux on a detector array. In addition, the bowtie filter is expected to be able to make the photons data on the detector array uniform in order to compress the dynamic range. Here, an overview of the progress made in the field of dynamic bowtie is presented, and basic principles of dynamic bowtie which are under the attention are introduced. The design theory of the dynamic bowtie for conebeam CT is discussed. In the end, the prospects for developing trends of the dynamic bowtie are proposed.