Abstarct: In this experimental research, we have studied the surface morphology, structural, thermo-electrical, electrical and optical properties of cadmium sulfide (CdS) nanostructure thin films prepared in different conditions by chemical bath deposition (CBD) method. For characterization of samples we have used: Scanning Electron Microscopy (SEM), Energy Dispersive X-ray (EDX), X-ray diffraction (XRD), Raman Spectroscopy, Seebeck effect, current-voltage (I-V) measurement, Ultraviolet-Visible (UV-Vis) spectroscopy, and photoconduction measurement of samples. In order to prepare CdS nanostructure thin films an aqueous solution including cadmium acetate (Cd (CH3COO)2 . 2H2O) as the source of Cd2+ ions, thiourea (H2NCSNH2) as the source of S2- ions, and ammonia solution (NH4OH) were used. In this research, in order to study the photoconduction property in CdS thin films the following quantities were considered as the variable parameters: time deposition and also annealing effect (Section 4-2), type of the substrate (glass and FTO) (Section 4-3), and finally pH variations (Section 4-4). Depending on the growth conditions, the SEM images of the samples indicated the formation of nano-grains with average sizes less than 100 nm. The X-ray diffraction patterns and also the thermo-electrical properties in all samples show the formation of amorphous and crystalline structure and n-type conductivity, respectively. Also it is found that annealing process lead to improve the structural properties together with the increment of donor-like defect concentration of the sample. These items in turn affect the electrical and optical properties of the sample including their band gap and also its photoconduction sensitivity.