Thin films of Ca1-xSrxCuO2 have been grown by alternate deposition of Ca1-xSrx and CuO2 atomic layers in a low pressure NO2 ambient. X-ray diffraction and its intensity analysis have confirmed the formation of an infinite layer structure of Ca1-xSrxCuO2 with x=0.2-1.0. The lattice constant c and electrical conductivity increase systematically with increasing Sr/Ca ratio. Clear diamagnetic signals at 90 K and 120 K have been observed in SrCuO2 and Ca0.2Sr0.8CuO2 films, respectively. In the Ca0.2Sr0.8CuO2 films, the onset of a small diamagnetic signal and a resistivity drop are also observed around 180 K.