The invention discloses chicken feed with functions of growth promotion and immunity enhancement. The chicken feed is prepared from the following components: 25-35 parts of bean dregs, 10-18 parts ofsweet potato starch, 8-15 parts of sweet potato leaves, 5-10 parts of apple pomace, 5-10 parts of carrot pomace, 5-10 parts of seaweed meal, 8-13 parts of locust powder, 8-13 parts of fishbone dust, 8-13 parts of animal liver powder, 4-6 parts of a Chinese medicine additive and 1-3 parts of a trace element supplement agent; and the Chinese medicine additive is prepared from 1-3 parts of radix codonopsis, 5-8 parts of radix astragali, 8-15 parts of fructus crataegi, 8-15 parts of pericarpium citri reticulatae, 15-25 parts of radix glycyrrhizae, 15-25 parts of fructus hordei germinates, 5-10 parts of herba taraxaci, 5-10 parts of fructus lycii and 15-25 parts of flos lonicerae. A preparation method of the chicken feed comprises the steps that moderate raw materials are weighed by mass proportion, crushed and then screened, and powder of all components is mixed, stirred and fermented; moderate Chinese medicine is weighed by mass proportion, crushed, screened, mixed and stirred, and the Chinese medicine additive is obtained through pressurization reflux extraction; and the moderate Chinese medicine additive and the trace element supplement agent are added in a mixed material, and the mixed material is mixed and stirred, and then put into a pelletizer for granulation.