The present invention discloses a continuous production process and devices of milk drink containing cereal grains. The devices include an aseptic tank, a heat exchange sterilization conveying pipeline, and a grain adding device. The devices are characterized in that: the grain adding device includes a plurality of precooking tanks, mixing tanks and quantitative putting mechanisms. Cereals are put into the precooking tanks, water washing, draining, precooking, and cooling are carried out, the precooked cereal grains are continuously and quantitatively added into the mixing tanks through the quantitative putting mechanisms from the precooking tanks, at the same time, milk or drink is injected into the mixing tanks to be stirred and mixed together, then the mixture is subjected to heat sterilization, the sterilized mixture is cooled, the cooled mixture is injected into the aseptic tank to be stored and stirred, and finally the finished products are obtained by filling. The existing sterilization machine and aseptic tank structures are utilized, which achieves the production of the drink containing cereal grains or milk, online adding and continuous automatic filling, avoids pipeline blockage, improves productivity and reduces production costs.