Abstract: A method for evaluating a surface cleanliness oriented toward additive forging of a metal substrate employs weight coefficients corresponding to oil contaminants, particles and chips. Contamination scores of different contaminants are determined separately by different methods, and a surface cleanliness thereof is characterized in a quantitative manner by calculating the sum of the product of the weight coefficient and the contamination score of each contaminant. Further, an accurate and systematic method for evaluating a surface cleanliness employs weight coefficient of each contaminant determined based on a degree of adverse influence of the contaminant on the interface bonding of a substrate. Different detection methods are used for different contaminants.