Abstract: A method for polyculture of Alosa sapidissima and Macrobrachium rosenbergii by a floating net fishing device and a greenhouse earthen pond includes: S1: providing a slope on an inner wall of a pond, and providing a feeding channel on the slope for survival and attachment of the Macrobrachium rosenbergii; S2: building a greenhouse on the pond, raising a water temperature to a set temperature, then putting Macrobrachium rosenbergii larvae, and putting Alosa sapidissima fry into the pond for polyculture in different periods; and S3: fishing in batches through a floating net: firstly, fishing the Alosa sapidissima fry in middle and upper layers, and then fishing the Macrobrachium rosenbergii in middle and lower layers.