In order to explore the effect of controlling the golden apple snail and heightening rice-output by breeding ducks of different kinds in paddy field, density and time of breeding ducks were investigated. Results showed that: The effect of controlling the golden apple snail was 93.94% when the time was 40 d. The effect on controlling the golden apple snail correlated positively with the density and time of breeding ducks when breeding density was 614/(667 m2) and average rice output increased with the increasing of breeding ducks, when the density reached 14/(667 m2), the controlling effect was the best. And the average rice-output attains tiptop. But when the density of breeding ducks was above 14/(667 m2), average rice output decreased with the increase of breeding ducks. The Jinding ducks exceled over the local sheldrakes distinct in controlling the golden apple snail and heightening rice-output.