The invention discloses a method and a system used for discriminating authenticity of the RMB. The method comprises steps that, an area sub graph of an ohm dragon ring pattern on the RMB is acquired; characteristics of the ohm dragon ring pattern in the area sub graph are identified; the characteristics are compared with those on a standard template; according to the comparison result, authenticity of the RMB can be discriminated. Through the method, the ohm dragon ring characteristics on the RMB can be utilized to identify authenticity of the RMB, and the method is simple and is easy to realize.