AbstractRare earth ions Er3+, La3+, and Y3+ have been introduced into the lattice of CdS nanobelts (NBs) to modulate its radiative recombination rate (RRR) during photoluminescence (PL) process. It is found that these ions have different quenching effects on the RRRs of direct interband transition and defect related transition. Only the former is greatly reduced through Er3+ doping, however, both of them are suppressed to a certain extent by La3+ and Y3+ doping. It is valuable that specific solid color luminescence can be realized through well‐chosen rare earth ions.