A　vertical　integration　of　indium　gallium　nitride/gallium　nitride　(InGaN/GaN)-based　microlight-emitting　diode　(mu　LED)　and　GaN　ultraviolet　bipolar　junction　transistor　(BJT)　phototransistor　(UVPT),　based　on　the　same　GaN　material　and　process　platform　(UVPT-mu　LED),　was　proposed.　The　integrated　device　is　a　novel　integrated　device　with　light-emitting,　detecting,　sensing,　driving　and　regulating　functions.　It　can　be　used　as　a　receiver　and　transmitter.　The　light-emission　effect　of　the　mu　LED　on　UVPT　can　be　regulated　by　changing　the　power　of　an　external　light.　Optical-electrical-optical　conversion　was　conducted　with　Silvaco　TCAD　software.　Electro-optic　modulation　characteristics　and　optical　power　amplification　were　attained　through　a　Silvaco　TCAD　simulation.　By　optimization　of　the　size　and　concentration　of　the　device　epitaxial,　the　current　gain　of　the　optimized　device　reaches　a　maximum　of　240.　The　UVPT-mu　LED　device　shows　a　strong　response　to　small-power　light　and　a　stable　response　to　high-power　light.　The　UVPT-mu　LED　chip　with　a　high　switching　ratio　was　successfully　prepared　and　used　to　verify　the　feasibility　of　the　UVPT-mu　LED　device.　The　proposed　monolithic　integrated　device　not　only　can　be　used　for　traditional　displays　but　also　shows　great　potential　in　intelligent　displays,　such　as　human-computer　interactive　systems,　on-chip　optical　interconnects,　photonic　chips　and　visible-light　communications.