Polypyrrole (PPy) nanowire network plates with both average length and width in tens of micrometers were prepared in an aqueous solution containing cetyltrimethylammonium bromide (CTAB) and nitric acid (HNO3) by chemical oxidative polymerization methods. It is found that PPy plates are constructed with double layers of nanowire networks. The influences of recipe such as the concentration of CTAB, HNO3, and pyrrole, as well as the reaction temperature on the morphologies of produced PPy were systematically investigated. By control experiment employing H2SO4 or HCl in place of HNO3, it is disclosed that HNO3 probably plays a key role in forming PPy plates. A plausible forming mechanism of PPy plate structures is offered. (C) 2009 Wiley Periodicals, Inc. J Appl Polym Sci 114: 3855-3862, 2009