A series of bulk ceramic samples of La1-xCaxMnO3 and Y1-xCaxMnO3 was prepared by the conventional solid state reaction method,and the samples of x=1/3 were investigated particularly.The colossal magnetoresistance phenomenon and the properties of magnetic and transport were studied in detail by the experiments of magnetic susceptibility and low temperature resistance.Small angle X-ray scattering (SAXS) was used to investigate the charge inhomogeneities in our samples at room temperature for the first time,and phase separation and colossal magnetoresistance phenomena induced by charge inhomogeneities above Tc were discovered.