1. A data processing method of a virtual optical disk, using in an optical disk system, comprising a physical optical disk play processing procedure, wherein the physical optical disk play processing procedure comprises a pre-processing and a buffer playing process, and wherein the data processing method of a virtual optical disk comprises steps of: executing a sound source determining procedure to obtain a sound source determining result; executing a virtual play processing procedure according to the sound source determining result, which comprises a virtual pre-processing and a virtual buffer playing process; and executing an optical disk backup procedure according to the sound source determining result; wherein when the sound source determining result is the virtual optical disk, the virtual play processing procedure is executed, when the sound source determining result is a physical optical disk, the physical optical disk play processing procedure is executed, and when the sound source determining result is a tape player of a radio, the optical disk backup procedure is executed.