Polycrystalline samples of La0.7Ba0.1Sr0.2Mn1-xCuxO3 (x = 0, 0.10) have been prepared by the sol-gel method. The x-ray diffraction (XRD) analysis shows both samples have achieved single phase state. Moreover, both samples crystallize in rhombohedral structure with R3̄c space group. Further analysis shows that copper reduces the unit cell volume of the sample, while at the same time reduces the average crystallite size of the sample. Copper substitution also leads to a slight distortion in the crystal structure of the sample. Scanning electron microscope (SEM) result reveals that copper substitution leads to a smaller grain size. Vibrating sample magnetometer (VSM) measurement at room temperature shows that copper substitution reduces the saturation of magnetic moment in the sample. This result indicates that copper substitution weakens the ferromagnetic property of the sample at room temperature.