The electronic and transport properties of borophene/phosphorene heterojunctions are systematically investigated by first-principles calculations. The geometrical structures and electronic band structures of monolayer borophene, monolayer phosphorene and heterojunctions with different distances between layers are analysed. The calculated results show that the band gap can be adjusted by tuning the distance between heterostructure layers. Then the transport properties of the heterojunction with different electrodes are also studied. It can be found that the selected different electrodes have significant effect on the transport property of the heterojunction. Interestingly, when the heterostructure is selected as the electrode, the heterostructure with an interlayer distance of 2.65 Å showed the best transport performance. It is hoped that this paper may provide useful insights for the design of nanoelectronic devices based on borophene/phosphorene heterojunctions.