Ca1-xSrxBi4Ti4O15 thin films were fabricated by sol-gel method on Pt(100)/Ti/SiO2/Si substrates. Influence of Sr content on the microstructure and ferroelectric properties of Ca1-xSrxBi4Ti4O15 thin films were systematically studied. The results indicate that Ca0.4Sr0.6Bi4Ti4O15 thin film has better ferroelectric properties with remanent polarization (2Pr) of 29.1+C/cm2, coercive field (2Ec) of 220 kV/cm. Furthermore, the film has good fatigue resistance. The better ferroelectric properties of Ca0.4Sr0.6Bi4Ti4O15 thin film originate from the relatively high concentration of a-axis oriented grains.