The influences of interfacial modification by various dyes (Eosin-Y, D205, N719 and N3) on structural, morphological, optical and electrical properties of CdS-based hybrid solar cells are investigated. Structural properties showed the cubic growth of chemical bath deposited CdS thin films. Morphological analysis indicated that CdS specimen had a smooth and crack-free surface whereas P3HT layer coated on CdS thin films displayed spherical grains with nonuniform distribution. According to Tauc's estimation conclusions, CdS and P3HT layers exhibited band gaps of 2.98 eV and 1.98 eV, respectively. The surface modification of CdS thin films by diverse dyes led to an increase in the absorption spectra of the CdS samples. Photoluminescence data showed that surface treatment of CdS samples by diverse dyes caused a decrease in the luminescence intensity of the CdS-based hybrid solar cells, meaning that efficient exciton dissociation was obtained. All the devices showed an obvious photovoltaic effect as a result of current density voltage (J-V) curves. Furthermore, the highest solar cell efficiency was achieved for ITO/CdS/N3/Ag device as 0.322%, which could be ascribed to the surface modification of CdS thin films, giving rise to a formation of better interface between CdS and P3HT layers.