The present invention discloses a security yarn containing a multi-composite spinning fiber and security products using the same. The multi-composite spinning fiber, according to the present invention, contains, in at least one or more kinds of polymer materials, a first component selected from an IR reactive pigment or an IR absorption pigment, a second component selected from a visible pigment or an invisible UV-reactive fluorescent pigment, and a third component selected from X-ray absorption materials, so that the security yarn containing the multi-component spinning fiber can be identified by infrared and ultraviolet wavelength and easily identified when irradiated with X-rays, thus providing a multi-identification capability and being useful for preventing counterfeiting. Therefore, the security yarn containing a multi-composite spinning fiber can be useful for preventing the counterfeiting of paper money, gift certificates, marketable securities, and passports or the like, preventing imitations of expensive brand-name products, or identifying a friend or a foe for military purposes.