It　is　a　critical　challenge　to　realize　efficient　GaN-based　UV　photodetectors　(UV-PDs)　due　to　the　existence　of　high-density　dislocations　in　the　epilayers　prepared　by　heteroepitaxy.　In　this　paper,　the　method　of　in-situ　modifying　the　screw　dislocations　in　GaN-based　materials　with　one-dimensional　(1D)　ZnO　nanorods　by　screw　dislocation-driven　self-assembled　solution　growth　is　developed　to　engineer　and　improve　the　photoelectric　performances　of　the　back-illuminated　metal-semiconductor-metal　(MSM)　structure　p-GaN　UV-PDs.　The　results　show　that　the　in-situ　grown　1D　ZnO　nanorods　on　the　dislocations　plays　the　roles　of　passivating　the　dislocations　to　suppress　the　dark　current,　improving　the　spectral　response　intensity　and　extending　the　spectral　response　band　of　the　MSM　structure　UV-PDs.　The　in-situ　modification　of　1D　ZnO　nanomaterials　can　be　developed　into　a　method　to　engineer　and　modify　the　defects　viz.　threading　dislocations　of　the　GaN-based　semiconductors　so　as　to　achieve　the　purpose　of　regulating　the　performance　of　the　related　optoelectronic　devices,　which　can　be　extended　to　other　material　systems　of　optoelectronic　devices.　©　2018　Elsevier　B.V.