The invention provides a marine shellfish fry intermediate-breeding device which comprises a breeding cavity for fry breeding and a water supply end for supplying water for the breeding cavity, wherein the water supply end comprises a water storage bucket for pumping water from a field pond and storing water, a water supply pipe is connected to the water storage bucket, the breeding cavity is a container provided with an open top and a planar bottom, a baffle is arranged in the breeding cavity, and the height of the baffle is lower than the side wall of the breeding cavity. The baffle divides the breeding cavity into a water storage tank and a breeding tank, the water supply pipe supplies water for the water storage tank, water overflows into the breeding tank through the baffle when the liquid level in the water storage tank is too high, a liquid discharging pipe is connected to the breeding tank and is communicated with the pond to achieve circulating water supply, and the position of a liquid outlet of the liquid discharging pipe is adjustable in height. The breeding device can solve the problems of low fry survival rate and difficult collection in the prior art, and high yield is obtained and large-scale fry production can be achieved by adopting an intermediate-breeding method.