A biosensor based on gold electrode modified by Pt nanaoparticles/Osmium redox polymer/Nafion trilayer film was fabricated and used for selective and sensitive determination of dopamine. The biosensor is explored for DA sensing using the cyclic voltammetry (CV), amperometric and differential pulse voltammetric (DPV) methods. The CV anodic peak currents showed a linear range with a correlation coefficient of 0.996, localized in the concentration range 0~192 μM. The differential pulse voltammetric (DPV) peak currents were linear with DA concentration during 2~425 μM with correlation coefficient of 0.99. The biosensor showed high sensitivity of 0.5 nA /nM cm2 and excellent reproducibility with the detection limit of ~10 nM (S/N=3) for the determination of DA. The easy fabrication, low detection limit and high sensitivity of the integrated biosensor making it particularly suitable for the analytical purposes.