The invention discloses a graphene viscose/graphene modal blended yarn, which is formed by interweaving graphene viscose spun yarn and graphene modal spun yarn, wherein the graphene viscose spun yarnis formed by spinning graphene viscose composite fiber with the graphene content of 0.5-4wt%, and the graphene modal spun yarn is formed by spinning graphene modal composite fiber with the graphene content of 0.5-4wt%. The invention also discloses a preparation method of the blended yarn and a fabric made of the blended yarn. According to the preparation method of the blended yarn, the graphene isintroduced into the viscose fiber or the modal fiber, the functional characteristics of the graphene are reflected on the viscose fiber and the modal fiber, the viscose fiber and the modal which areexcellent in performance are given good electrical conductivity, thermal conductivity, antibacterial property, anti-ultraviolet function, far-infrared function and the like, and the mechanical properties of the viscose fiber and the modal are improved.