Superradiance is known as the enhancement of spontaneous radiation due to build-up of a collective dipole. Our work is to investigate whether superradiance plays any role in the otherwise extremely weak relaxation of ultracold polar molecules, and whether it can be utilized for laser cooling, which is as of yet inaccessible for molecules. We report our investigation on superradiance in multilevel particles, which serve a good approximate for the low-lying quasiharmonic vibrational levels of polar molecules. This approach may shed a light on manipulation, e.g., cooling of vibrational modes of polr molecules when superradiant mechanism is considered.