The aerodynamic drag of the spacecraft in Very Low Earth Orbit (VLEO) has an important effect, and the implementation of Atmosphere-Breathing Electric Propulsion (ABEP) is anticipated to facilitate long-duration, cost-effective missions in VLEO. The balance between the acquisition and utilization of resources and aerodynamic drag should be considered in the geometric design of spacecrafts based on the ABEP system. This study defines the normalized propellants (R-m) and the normalized power (R-P) on the basis of the continuous equilibrium of thrust and drag, with drag calculated via the panel method derived from rarefied gas dynamics. The expression for R-P & sdot;R-m is formulated under the cylindrical configuration, and then the aspect ratio (l/d) is identified as the key variable. With the constraints R-m >= 1 and R-P >= 1, and the maximization of R-P & sdot;R-m as the optimization goal, the optimal aspect ratio ((l/d)(opt)) is determined, where skin friction is equivalent to pressure drag. Consequently, the lower limit of the feasible orbital altitude for the cylindrical configuration is calculated to be 186 km, which corresponds to an atmospheric density of 4.01 x 10(-10) kg/m(3), based on the performance parameters of the existing the intake device, electric thruster, and solar panels. This study further analyses the influence of orbital environmental parameters and the spacecraft's core parameters on the specific impulse (I-sp) and the product of the normalized power and the normalized propellants (R-P & sdot;R-m). The analysis is extended to encompass columnar geometries with arbitrary cross-sections, revealing that spacecrafts with a flattened cross-sectional configuration exhibit a significant advantage in VLEO. Subsequently, an optimization process is carried out, focusing on a basic configuration that integrates a flattened cylindrical shape with wings. This research provides critical insights for the integrated design of spacecrafts employing the ABEP system in VLEO.