Polyaniline multidimensional architectures from plate-like structures to flower-like superstructures have been successfully tailored by the oxidation polymerization in dilute aniline solution at room temperature, when the molar ratio of oxidant to monomer was altered in the range of 0.1:1-0.8:1. It was found that at low molar ratio (0.1:1-0.3:1) plate-like structures could be synthesized, while the as-synthesized product at the higher molar ratio (0.4:1-0.8:1) was flower-like superstructures; and the effect of monomer concentration on the shape of plate-like or flower-like architectures was also investigated. More importantly, their growth processes have been followed by measuring the morphological evolutions and chemical structures of products with the different reaction times, and then a plausible interpretation to their formation was brought forward through discussing the polymerization courses at two molar ratios (0.2:1 and 0.6:1). Besides, the molecular weight and conductivity Of products obtained were also measured in this report.