Without doping any rare-earth ions, Ca3SnSi2O9 emits blue light and exhibits weak long-lasting phosphorescence. By selecting appropriate rare-earth ions doped into the host, multicolor phosphorescence can be obtained from Ca3SnSi2O9:Re3+ (Re = Pr, Tb, Sm) after excitation at 316 nm, which is due to the persistent energy transfer between the host and rare-earth ions. The thermoluminescence results indicate that the introduction of Re3+ (Re = Pr, Tb, Sm) produces more suitable traps (V ''(Ca)) depth at 360 K, which make an important contribution to the more excellent long persistent luminescence phenomena.