Rearing of Tilapia mosambica in the rice fields and the correlation between the fishes andthe rice plants, has been studied during the years of 1962-1964 in Amoy, Fukien Province.The physical, chemical and biological environments of the rice fields have been observed andmeasured once a month. The physical properties of the rice fields differ greatly with those of fish ponds. ButTilapia adapts itself favorably to these shallow water environments. The chemical properties of the rice fields are basically good for fish stocking. Dissolvedorganic matters are plentiful in the rice fields. The content of inorganic salts (NO₃^一, PO₄^三,SiO₃^二) in the fields stocked with fishes, are much higher than the fields not stocked. It isaffected by the excrement of the fishes. A large number of aquatic organisms inhabits the rice fields. 99 species of plankton,34 species of aquatic plants, and 17 species of bottom dwelled invertebrates and insects havebeen collected and observed. Most of them are directly or indirectly used as food by theTilapia. The average yield of fish from rice fields in four months of rearing, is 170 kg. perhectare. When stable manure is added, the production can be increased to 206-315 kg. perhectare. Besides, an additional production of few ten thousands of Tilapia fries have beenreproduced during the months. Regarding the growth of the rice plants, those in the fields stocked with Tilapia growsmuch better than in the fields without fish. And the yield of rice of the former is 3.0-13.2%greater than the latter. The experiment shows that the rearing of Tilapia mosambica withgrowing rice has a beneficial effect on rice production.