Controlled assembling of Sn3O4 nanoflakes over multi-wall carbon nanotubes (CNTs) was achieved for the first time by using a facile hydrothermal method. The SEM and TEM images showed that numerous Sn3O4 nanoflakes were widely assembled over the surface of CNTs. In these hybrids, the CNTs served as dispersing-template could reduce the agglomeration of Sn3O4 nanoflakes, as well as facilitate the interfacial charge transfer because of its high electrical conductivity. The Sn3O4-CNTs photocatalysts have exhibited remarkably promoted performances in decomposing organic contaminant under visible or solar light. The Sn3O4-CNTs hybrid with CNTs mass ratio of 4.37% exhibited the best activity under visible light, while that with CNTs mass ratio of 1.41% was more efficient when irradiated by solar light, the activity of which was about 3.47 times higher than that of pristine Sn3O4 under identical conditions. Controlled experiments proved that center dot O-2(-) and h(+) played the chief role in decomposing organic pollutants.