Besides the conventional strong and electromagnetic decay modes, the J/ψ particle can also decay via the weak interaction in the standard model. In this paper, nonleptonic J/ψ → D s,d π, D s,d K weak decays, corresponding to the externally emitted virtual W boson process, are investigated with the perturbative QCD approach. It is found that branching ratio for the Cabibbo-favored J/ψ → D s π decay can reach up to O(10 −10 ), which might be potentially measurable at the future high-luminosity experiments.