Three-layer structured composite films consisting of a rutile titanium dioxide (TiO2) film, a cuprous oxide (Cu2O) nanofilm, and silver (Ag) particles were successfully prepared through sputtering and annealing procedures. The variations in microstructures and photoactive properties of the composite films were investigated by varying the sputtering duration of Cu2O and Ag. The photoelectrode made of the Ag particle/Cu2O/TiO2 composite films exhibited superior photoelectrochemical and photocatalytic properties in comparison with those of the Cu2O/TiO2 bilayer films and pristine TiO2 film. The surface plasmon resonance of Ag particles promotes the photon absorption capacity of the Ag particle/Cu2O/TiO2 composite films. Moreover, the Ag particles on the Cu2O nanolayer act as effective electron traps, thus preventing recombination of photoinduced carriers under irradiation and prolonging the carrier lifetime, thereby increasing the carrier transfer rate. The Ag particle/Cu2O/TiO2 composite film with a surface Ag/(Ag + Cu) atomic ratio of 70.81% exhibits superior photoelectrochemical and photocatalytic properties in comparison with the other Ag particle/Cu2O/TiO2 composite films prepared with different Ag sputtering durations. The suitable Ag particle content is an important factor affecting the photoactive performance of the Ag particle/Cu2O/TiO2 composite film. The scavenger test results demonstrate that the photodegradation mechanism of the Ag particle/Cu2O/TiO2 composite film towards methyl orange solution under irradiation follows a Z-scheme mechanism.