The invention provides a drug for treating onychomycosis and fungi dermatosis, which includes immersion agent and spray paint. Raw materials for preparing the immersion agent include 84 disinfection solution, garlic roots and the potassium permanganate solution with the weight percentage of 0.08-0.15 percent. Drug raw materials for preparing the effective components of the spray paint include sophora, coptis, common cnidium fruit, safflower and Szechwan Lovage Rhizome. Combining Chinese medicine with western medicine, the drug for treating onychomycosis and fungi dermatosis can be used conveniently without the oral administration, solves the hard problem that oral therapeutic drugs damage internal organs, has non-toxic harmless to human bodies, is provided with good therapy effect which is greatly higher than commonly used treating drugs at present, can thoroughly sterilize bacteria to eliminate the reproductive capacity of the bacteria, recovers the original appearance of healthy skin and nail and relieve the special metal pressure of onychomycosis and fungi dermatosis of patients.