Bowtie filter, as a beam shaping attenuator placed between X-ray source and scanned object in computed tomography system, can effectively reduce radiation dose. In addition, the bowtie filter is expected to be able to compress the dynamic range which could limit the application of some detectors. In this paper, we propose a methodology for dynamic bowtie which can balance the photon flux on a detector array in real time. Our goal is to determine the shape of dynamic bowtie filter for modulating detector reading in the target angle of 20° with a reflected target. Monte Carlo simulation has been employed. The results demonstrate the designed high-attenuation bowtie filter has a unique advantage in terms of balancing photon flux data on a detector array.