Production of one dimensional nanomaterials with secondary morphology exhibiting unique functions is challenging. Here we report that a nanoscale immiscible polymer blend solution the electrojet can assemble into ultraporous interweaving microfibers. This intriguingly novel morphology originated from a blend of polycaprolactone (PCL) and polyethylene oxide (PEO) in a DCM-DMF mixed solution when the ratio between each component reached a threshold and when the electrospinning parameters were delicately controlled. We further investigated their influence on cell infiltration and colonization. The hierarchical porosity enhanced cell infiltration and proliferation significantly.