In our previous work, it was found that large Bird's Nest patterned nanofibrous membranes can be simply electrospun from chlorinated polypropylene solution doped with an ionic liquid, and a plausible formation mechanism of Bird's Nest patterned architectures was proposed. Here, we use Ansoft Maxwell version 12 software (3D, electrostatic solver) to simulate the electrical field distribution of the electrospinning setup, and to clarify the rationality of proposed formation mechanism. Calculation results clearly show that the introduction of charged nanofibrous bundles would produce a similar patterned electrical field distribution, which definitely confirms the important role of surface residual charges. The proposed mechanism can be well extended to other polymer systems including polystyrene, poly(acrylonitrile-co-acrylic acid) and chitosan/poly(ethylene oxide).