The generation of FWM going with PPLN-OPO was put forward for the first time. FWM frequency matching and quasi-phase matching conditions of bumping wave λ 3 (1064 nm), signal wave λ 1 (1500 nm) and idle wave λ 2 (3660.55 nm) in PPLN-OPO was discussed. The system of PPLN-OPO-FWM process was set up theoretically and the setting of optical system was realized experimentally. The conclusion of experiment was accorded with theoretical analysis, which is valuable for the study of PPLN, OPO and FWM in theory and practice.