The invention belongs to the technical field of greenhouse gas detection, and provides a collection device and a determination method for determining emission contribution of endogenous greenhouse gases in a shallow water body. The collection device comprises a bottom ring, the bottom ring is in threaded connection with a plurality of middleware, the topmost middleware is in threaded connection with a top ring, water inlets and outlets are formed in the middles of the middleware, sealing cover plates are arranged at the positions corresponding to the water inlets and outlets, and springs are arranged between the sealing cover plates and the middleware. According to the invention, through the arrangement of the middleware, the top ring and the bottom ring, under the combined action of an internal thread and an external thread, the middleware, the top ring and the bottom ring can be combined to form a box body meeting the sampling environment and the required height, and greenhouse gases generated by an in-situ water body, a water-gas interface, sediments and the water body can be respectively collected; and the contribution value of the device to the greenhouse gas emission of the water-gas interface is calculated through a calculation formula, and the device is simple and stable in structure, can be detached and carried and is relatively convenient to use.