1. A fluorescent color scanning method comprising the steps of: (a) using a light source of a predetermined brightness to scan a standard white so as to obtain a first reference white W1(R,G,B) in which R indicates red color; R indicates green color; B indicates blue color; (b) reducing the brightness of said light source, and then scanning said standard white to obtain a second reference white W2(R,G,B); (c) using said first reference white W1(R,G,B) as the standard to scan every scanning point and then storing the scanned result of each scanning point by means of Pm(R,G,B), in which m=1, 2, 3. .. , m that represents the respective scanning point; (d) using said second reference white W2(R,G,B) as the standard to scan every scanning point of the document to be scanned and then storing the scanned result of each scanning point by means of Qm(R,G,B); and (e) comparing the value of Qm(R,G,B) to the value of W2(R,G,B), so as to determine if the document contains a fluorescent color or not subject to: (i) determining that the document contains a fluorescent color if Qm(R)>W2(R), Qm(G)>W2(G), or Qm(B)>W2(B), and then converting said Qm(R,G,B) into the accurate color output Om(R,G,B) based on said W1(R,G,B) through a conversion method, and (ii) determining that the document contains no fluorescent color if Qm(R)≦W2(R), Qm(G)≦W2(G), and Qm(B)≦W2(B), and then using the value of Pm(R,G,B) as the image output value.