The invention relates to the technical field of medicaments, in particular to a medicinal composition for treating skin eczema and itching and a preparation process thereof. The medicinal composition is prepared from the following raw materials in parts by weight: 10-15 parts of zanthoxylum bungeagum maxim, 20-25 parts of gypsum, 8-10 parts of cortex phellodendri, 4-6 parts of indigo naturalis leaf powder, 3-5 parts of Chinese lizardtail rhizome or herb, 6-12 parts of fructus kochiae, 5-8 parts of mentha haplocalyx herba, 1-3 parts of borneclum syntheticum, 0-2 parts of liquorice root, 2-5 parts of rhizoma et radix notopterygii, 3-6 parts of radix achyranthis bidentatae, 0-3 parts of radix puerariae, 1-3 parts of cortex magnoliae officinalis, 0.5-4 parts of periostracum cicada, 0-2 parts of herba schizonepetae, 1-3 parts of radix saposhnikoviae and 1-2 parts of radix sophorae flavescentis. In the medicinal composition, traditional Chinese medicines are combined reasonably; the gypsum, the cortex phellodendri and the indigo naturalis leaf powder which are used together can achieve the effects of clearing away heat, healing sore and promoting tissue regeneration; the periostracum cicada, the herba schizonepetae, the radix saposhnikoviae and the radix sophorae flavescentis which are used together can promote eruption and relieve convulsion; the zanthoxylum bungeagum maxim, the Chinese lizardtail rhizome or herb, the liquorice root, the rhizoma et radix notopterygii, the radix achyranthis bidentatae, the radix puerariae and the cortex magnoliae officinalis which are used together have the effects of removing dampness, relieving pain, killing insects, detoxifying, relieving itching and removing fishy smell; the fructus kochiae can achieve the effects of clearing heat, promoting diuresis, dispelling wind and arresting itching. The traditional Chinese medicinal composition provided by the invention has a remarkable curative effect on skin eczema and itching, is low in preparation cost, is convenient to use, and has a clinical curative rate being up to 98 percent.