CdSe nanoparticles were prepared in aqueous medium using chemical method.XRFspectrum reveal both Cd and Se. XRD spectrum shows that CdSe nanoparticles have hexagonal structure, From XRD, Crystallization size85.6 nm, lattice constant C7.28Aæ%, effective strain2.*10-4(linÂ2mÂ 4)between the nano crystals and dislocation (irregular)2.85*10-4 ( .. ) linmï4 were determined. FTIR spectrum shows some toxicity in CdSe nanoparticles suchO-H. FromImpedance Spectrumof CdSe,activation energy 0.0275 eV and the density ofcarriers charge were determined. FromC-V characteristic type of semiconductor and it was found to be n- type. CdSe hastwo donors levels (Nd1=3.06*1022 cm-3 ,Nd2=6.12*1022 cm-3). Finally,the derivation of capacitance respect in function of temperature, fromits graph energy diagram of CdSe nanoparticles was plotted.