Abstract: Income approach is the most widely used method, but difficult to calculate the discount rate, in business valuation appraisal. The discount rate is composed of three parts: risk-free return rate, industry average risk return rate and enterprise-specific risk-adjusted factor. The existing studies are mostly on the riskfree return rate and industry average risk return rate, but the enterprisespecific risk-adjusted factor in nonlisted companies is scarcely touched, and thus there is no more comprehensive, scientific, unified, proven method of calculation, forcing the appraisers to depend on subjective judgment in real work. The Wall method can solve the problem in the calculation of enterprise-specific risk adjustment factor and hence, in a sense, offers a solution to appraisers in determining the enterprise-specific risk adjustment factor.