A novel method is presented to enhance the resonant transmission contrast ratio in metal-insulator-metal (MIM) sidecoupled- cavity waveguide. The finite difference time domain (FDTD) method is used to simulate and study the optical properties of the filter based on double side-coupled cavities structure with optofluidics pump system (OPS). This system provides a flexible way to change wavelength in the optical filter. In the numerical simulation, the resonant wavelengths from 1000 nm to 1550 nm are analyzed. We find that the double side-coupled cavities structure with OPS has higher onresonance transmittance and better wavelength selectivity than the single side-coupled cavity structure with OPS.