The invention discloses a method, in which liquid nitrogen is sprayed during the crushing and concocting process of Chinese medicinal herbs to prevent oxidation and browning. The herbs need to be crushed into dead smalls in the industrialized machining of the Chinese medicinal herbs, but medicinal herbs are hard to be crushed because fibers and pectine are contained; the prior crushing method leads active ingredients in the medicinal herbs to be volatilized and lost caused by the generated heat, and hastens the oxidative cleavage of the active ingredients in the Chinese medicinal herbs to cause brown stain, so as to result in the decreased quality of the Chinese medicinal herbs. The method has the technical proposal that the Chinese medicinal herbs are selected; the impurities are removed; the drying is acted; the pre-cutting is executed; the temperature in a cavity body of a muller is set; the quantified liquid nitrogen is sprayed when crushing. Under the condition that the active ingredients are not changed, the method leads the crushing and the concocting of the Chinese medicinal herbs to be acted at the low temperature by utilizing the brittle fracture of the liquid nitrogen, the original physiological activity of the Chinese medicinal herbs can be remained to the utmost extent, the various nature functional components contained in the Chinese medicinal herbs are protectedduring the crushing process, and the production technology level as well as the modernization of the traditional Chinese medicine are promoted greatly.