Motivated by multi-commodity flow supply chain network that composed of multiplemanufacturers, multiple retailers and multiple consumers, an equilibrium model whichestimates the products flow of the whole supply chain network and market price is set up bythe use of variational inequality. This paper analyzes the influence of RFID investment onproduct demand, where the RFID cost is shared by the manufacturers and retailers accordingto certain proportion, and develops competitive equilibrium among the members incombination of variational inequality and Nash equilibrium theory. Additionally, thevariational inequality model of market equilibrium is set up; meanwhile, we obtain thevariational inequality model of multi-commodity flow supply chain network under thecondition where the demand depends on technology investment. Finally, its feasibility isverified with numerical analysis, and several extensions of the model are considered as well.