Sr-doped LaTiO3 (SLTO) thin epitaxial films on LaAlO3 (100) have been fabricated by the off-axis rf magnetron co-sputtering system. The dopant Sr2+ ions were expected substituting La3+ ions in the films to introduce the hole carriers. The X-ray diffraction shows that the  direction of the SLTO films is perpendicular to the substrate surface. The in-situ grown specimens were measured the temperature dependence of resistivity and the Hall coefficients to study the transport properties. The Hall measurements show that the carrier is electron for Sr-doping over 16%. The temperature dependence of the resistance shows that the n-type films are metallic and deviate from free electron gas model obviously. We found the behaviour could be well described by the small-polaron coherent motion model.