In some cold-atom experiments, it is necessary to measure the density distribution of cold atoms in advance and provide data support for subsequent experiments. The previously established manual method is no longer suitable for such experiments. In this study, we propose a new method for measuring the density distribution of cold atoms during a single preparation period of cold atoms. The proposed method uses a pair of anti-Helmholtz coils and a pair of Helmholtz coils to generate gradient and bias magnetic fields, respectively. By adjusting the Helmholtz coil current, the position of zero point of the total magnetic field can be changed, the contribution of atoms at different positions to the probe light absorption can be affected, and finally, the atomic density distribution can be measured. The feasibility of this method is analyzed theoretically, and an experimental scheme for fast cold atom density measurements is proposed.