The invention relates to a method and a device for the chain velvet making of a multi-crystalline solar cell. The invention adopts an overflow mode from four sides of a groove body to enable liquid to quickly overflow after reaction, and adopts a top spray mode that medical liquid is directly replenished to the periphery of silicon chips from the upper part so that the medical liquid can sufficiently contacts with the silicon chips, the temperature of the medical liquid is more beneficial to control and can be kept uniformly and velvet making effect can be improved. The invention adopts a liquid feeding mode from the groove bottom in the groove body, an liquid inlet faces downward, a liquid feeding pipeline is processed to control regulated flow, the upper part of an internal groove is provided with a weir crest, liquid entering from the liquid feeding pipeline upward overflows to the weir crest and flows into an external groove, the bottom of the external groove is provided with a liquid return opening which is connected with a medical liquid circulation supply groove through the pipeline, and the medical liquid flows back to the medical liquid circulation supply groove by gravity. The invention has the advantages of more easily controlling the temperature, effectively improving velvet making effect and product quality and reducing reflectivity, the temperature control accuracy can reach within +/-1 DEG C, and the reflectivity after velvet making can reach below 20 percent.