In this paper,we investigate the non-static massive string magnetized barotropic perfect fluid cosmological models in Rosen's (Gen.Rel.Grav.Vol.4 (1973) 435) bimetric theory of gravitation. Using the relation isotropic pressure 'p' directly proportional to energy density 'ρ' ( i.e p = Є1 ρ , where -1 ≤ Є1 ≤ 1) , dust filled geometric string model and stiff fluid filled model of the universe are obtained. Some physical and geometrical behavior of the exhibited models are also discussed.