Dopamine (DA), a biological neurotransmitter which has a similar structure to the essential adhesive component of mussel protein, was here used to modify polyaniline (PANI) via a one-step chemical oxidization method. The as-fabricated DA-PANI resulted from different DA to aniline (An) mole ratio showed different morphology. Compared to pure PANI, the modified PANI exhibited greatly enhanced adhesion force to the substrate. In addition, the biocompatibility and dispersibility of DA-modified PANI were also significantly improved compared with pure PANI. More importantly, the incorporation of poor conductive PDA did not enormously weaken the electrical conductivity of PANI, and it still showed good electrical conductivity as the DA/An mole ratio was not higher than 0.48.