Abstract: In view of the limitations of the traditional DC channel in terms of pressure drop and local water accumulation, a bionic droplet variable section flow channel is established, and the number of water droplet sequences and runners is used as the main control geometric variables to construct a systematic design space. Then, a three-dimensional numerical model is established to carry out group comparison calculations under the same boundary conditions and operating conditions under the condition of equal-size DC channel as a control. Then, statistical tests were used to evaluate the significance of the influence of parameters. The evaluation system covers the uniformity of pressure drop and water distribution. The results show that the bionic droplet variable section runner is better than the DC channel in many indicators, and the bionic droplet variable section runner can strengthen the uniformity of water distribution while controlling the pressure drop, so as to realize the synergistic optimization of mass transfer uniformity and water management, and provide a quantifiable parameter space and methodological basis for the biomimetic design of battery runners.