The invention provides a post-processing method for raw silk. The post-processing method for the raw silk comprises the following steps that: (1) a small silk winding device is taken off from a reeling machine, the small silk winding device and a strand on the small silk winding device are placed in a drying room to be dried and temperature of the drying room is maintained to be 40 to 50 DEG C; (2) the dried strand and the small silk winding device are placed in a sealed container and are soaked and wet in a vacuum condition, a weft soaking auxiliary agent is added to soaking liquid, vacuum degree of the vacuum condition is interrupted for several times, ordinary pressure is recovered and then the sealed container is vacuumized again so that the vacuum condition is formed, and the strand and the small silk winding device are soaked under the vacuum condition; and (3) the small silk winding device after being soaked at step (2) is re-reeled so that a large silk sheet is obtained, large reeled silk is obtained through weaving and detection, silk sheet balance, color match and package and the large reeled silk directly serves as silk knitted on a machine. According to the post-processing method for the raw silk, a comprehensive processing mode is adopted, so that processes of detaching, soaking and drying the reeled silk are reduced, a processing procedure of the raw silk is shortened, the post-processing method for the raw silk has the advantages of being easy to operate and capable of improving production efficiency.