The effects of external strain on the electronic structure and carrier mobility of graphitic blue phosphorus are investigated theoretically. Symmetry breaking induced by the in-plane strain not only modulates the band structure, but also changes the carrier population at the valence band maximum and conduction band minimum so that the transport current density can be regulated. Compressed deformation in the direction normal to the plane transforms the blue phosphorus into an in-plane structure and the superfluous electrons reduce the band gap giving rise to a semiconductor-metal transition. Our theoretical assessment reveals that strain engineering is a useful method to design electronic devices. (C) 2015 Elsevier B.V. All rights reserved.