The present work reports a simple method to fabricate superhydrophobic porous polymeric surfaces by a phase separation process. The method involves the in situ polymerization of butyl methacrylate (BMA) and ethylene dimethacrylate (EDMA) in the presence of co-porogens of 1,4-butanediol (BDO) and N-methyl-2-pyrrolidone (NMP) to afford superhydrophobic surfaces with the micro/nano roughness structure. The influences of the polymerization mixture on the morphology and hydrophobicity were investigated by adjusting the composition of the co-porogens and the mass ratio of monomers to co-porogens, respectively. And a precise description of the underlying mechanism of the microstructure formation was presented. The as-prepared surface shows a superhydrophobicity with water contact angle (WCA) of 159.5° and low sliding angle (SA) of 3.1°. Moreover, the superhydrophobic surface shows good chemical stability with better resistance to acid, alkali or salt aqueous solutions and excellent thermal stability. The method is simple and low-cost and can be used for the preparation of the self-cleaning superhydrophobic surfaces.