The concentration of nitrous oxide in the atmosphere is only two orders of magnitude lower than that of Carbon dioxide, however, its green house effect is about 200-300 times higher than that of carbon dioxide. So it has been considerably concerned in the past decades and lots of work have been carried out. A review of the study on biogeochemical cycle of nitrous oxide in oceans for the past decadets is presented here. The vertical distribution of nitrous oxide in oceans, their impact factors, as formation and removal mechanisms will be discussed in more detail. The N₂O cycles in oceans will play a significant role in the global biogeochemical cycle.