The invention provides a three-dimensional breeding device and breeding method of kelp and laver. The three-dimensional breeding device comprises kelp raft frames and a laver net, wherein a floating rope is arranged on each kelp raft frame, a kelp seedling rope is arranged between every two floating ropes, and the kelp seedling rope is located at the bottom of each floating rope; and the laver netis arranged between the floating rope and located above the kelp seedling rope, a surrounding rope is arranged in the circumferential direction of the laver net, two ends of a short edge of the surrounding rope are respectively and detachably connected with the floating ropes, snap rings are further arranged on the long edge of the surrounding rope, and clips adaptive to the snap rings are arranged on the floating ropes. The invention also provides a method for performing three-dimensional breeding on kelp and laver through the breeding device. According to the three-dimensional breeding device and method disclosed by the invention, the kelp is at lower parts, the laver is at upper parts, three-dimensional breeding of the kelp and the laver is realized, bamboo poles and large cylindricalfloats are not needed, accumulation of floating horner sargassum frond is avoided, the laver is high in growth speed, good in quality and high in yield, the kelp is flourishing in growth, the resources are effectively utilized, seawater environment pollution caused by spilling of dilute hydrochloric acid on the sea surfaces is avoided, and the three-dimensional breeding device is simple in structure, convenient to manage and good in economic benefits.