Preparation of a poly(styrene-co-divinylbenzene-co-methacrylic acid) monolithic stationary phase for the use in capillary electrochromatography (CEC) has been improved by optimizing the polymerization conditions. It is observed that the reaction time strongly affects column efficiency, while the proportion of isooctane in porogen influences peak symmetry of some solutes seriously. The lifetime of the monolithic columns prepared mainly depends on the pH of buffers used. Reproducibility of electroosmotic flow (EOF) from batch to batch columns are lower than 2.8% relative standard deviation. Unlike other types of capillary electrochromatographic monoliths, a pH-dependent EOF was observed on this type of column. Separation of various types of compounds including aromatic hydrocarbons, hormones, anilines, basic pharmaceuticals, and peptides was achieved. The facile preparation and wide application of this monolithic column may make styrene-based polymer a potential stationary phase in CEC.