Abstract: The photoinduced charge carrier dynamics is one of the important factors that affect the photocatalytic performace of semiconductor composites. In this work, tin oxides nano-particles were successfully fabricated by one-step solvent thermal method using SnCl₂·2H₂O as raw material and NaOH as precipitant. The fabricated samples were characterized by SEM, XRD, TEM and Uv-Vis spectra. The results show that about 10-20 nm particles size SnO-SnO₂ composites and about 10 nm tetragonal SnO₂ particles can be obtained by adjusting the reaction condition. Photocatalytic degradation performance of the above two nano-materials has been evaluated by using Rhodamine (RhB) as the degradation agent. The degradation time of RhB can be reduced by 50% by using nano SnO-SnO₂ composites as photocatalyst compared with pure nano SnO₂ particles. For further studying the mechanism for this result, transient surface photovoltage (TSPV) technique has been carried out to understand the photoinduced charge carrier dynamics of the resulting materials. The corresponding results show that the photoinduced charge carrier separation has been enhanced, the surface recombination of photoinduced charge carrier has been reduced, and the lifetime of photoinduced charge carrier on the material surface is prolonged by building the nano SnO-SnO₂ composites. Finally, the consequent photocatalystic performance is enhanced.