The invention relates to a full-automatic efficient cotton-filling machine. The machine comprises a case, an inner cavity of the case is divided into a first case cavity and a second case cavity through a division board, the first case cavity is internally provided with a cotton loosing mechanism, the second case cavity is internally provided with a driving mechanism and a cotton conveying fan, the driving mechanism is in transmission connection with the cotton loosing mechanism, a cotton conveying mouth is formed in the case, a conveying mechanism is arranged on the side, close to the cotton conveying mouth, inside the first case cavity, the other side of the conveying mechanism is connected with the cotton conveying fan through an air pipe, an annular platform is arranged at a connector of the cotton conveying mouth and the case, a circle of annular groove is formed in the outer wall of the annular platform, a rotatable connecting sleeve is arranged on the annular platform through the annular groove in a clamping and sleeving mode, the connecting sleeve is fixedly connected with the cotton conveying mouth, the length of the cotton conveying mouth is smaller than that of a pillow case, and multiple uniformly distributed air holes are formed in the peripheral wall of the cotton conveying mouth. According to the cotton-filling machine, cotton can be scattered rapidly, cotton filling is uniform, and it is guaranteed that after filling is conducted, the fluffy effect of a pillow is good.