Abstract: Graphene has prominent conductivity, fast charging transfer rate, high specific surface area, good chemical and thermal stability, and has high research value on the application in solar cells. Mechanical stripping method was used to prepare graphene and through low-temperature spin coating method, graphene solution were coated on the FTO conductive glass and applied to QDSCs. In this experiment, the electrode properties of different thick layers of graphene with different spin-coating times were analyzed. With the increasing of spin coating time, the exchange current density increased first and then decreased on the counter electrode, the short-circuit current density (J_sc) and battery efficiency trend to increase first and decrease later. The experiment shows that, when spin coating time is 30s, exchange current density (J₀) of graphene electrode reaches a maximum, show good electrical activity to electron hole, fitting data shows that the graphene line data of R_ct of graphene counter electrode is 2.049 Ω·cm² based on Tafel polarization curve data, short-circuit current density increased to 5.21 mA·cm^-2, the efficiency of QDSCs increased to 1.87%. Electron microscopic test of graphene shows that the spin-coating time is 30 s corresponding to the thickness of graphene film is 2 μm, the graphene electrode give out best performance.