In this work we investigate novel, agarose-based polymer electrolyte that is modified by magnetic NiO nanoparticles for solid-state dye-sensitized solar cells (DSSCs) applications. After proper treatment under an external magnetic field, the agarose electrolyte exhibits increased ionic conductivity and better penetration into the mesoporous TiO2 photoanode film, which improves the power conversion efficiency of the DSSCs. Electrochemical impedance spectroscopy measurement is also performed to analyze the magnetic field effect on cell performance. After applying proper magnetic filed intensity, the recombination resistance and redox transport resistance in the devices are improved. This method can be possibly applied to other solid-state electrolyte materials to improve their performance and can lead to more efficient DSSCs.