In the two-quark model supposition for the meson a(0) (1450), which can be viewed as either the first excited state (scenario I) or the lowest lying state (scenario II), the branching ratios and the direct CP-violating asymmetries for decays B -> a(0)(1450)rho(omega) are studied by employing the pert urbative QCD factorization approach. We find the following results: (a) For the decays B- -> a(0)(0)(1450)rho(-) and (B) over bar (0) -> a(0)(+)(1450)rho(-), their branching ratios have large difference between two scenarios. Although their branching ratios are larger than other considered decay modes, their direct CP-violating asymmetries in both scenarios are small. (b) For the decays B- -> a(0)(-)(1450)rho(0) and (B) over bar (0) -> a(0)(-)(1450)rho(+), a(0)(0)(1450)rho(0), a(0)(0)(1450)omega, their branching ratios are close to each other between two scenarios, respectively. (c) Comparing with the decays (B) over bar (0) -> pi(0),rho(0),pi(0),pi(0), the decay (B) over bar (0) -> a(0)(0)(1450)rho(0) receives a larger branching ratio in each scenario, which is sensitive to the variation of the Cabibbo-Kobayashi-Maskawa angle alpha.