A prototype of full-color active-matrix micro-light-emitting diode (micro-LED) micro-display with a pixel density of 391 pixel per inch (ppi) using InGaN/AlGaInP heterogeneous integration is demonstrated. InGaN blue/green dual-color micro-LED arrays realized on a single metal organic chemical vapor deposition (MOCVD)-grown GaN-on-Si epiwafer and AlGaInP red micro-LED arrays are both monolithically fabricated, followed by the integration with a common complementary metal oxide semiconductor (CMOS) backplane via flip-chip bonding technology to form a double-layer thin-film display structure. Full-color images with decent color gamut and brightness are successfully displayed through the fine adjustment of driving current densities of RGB subpixels. This full-color display combines the advantages of high quantum efficiency of InGaN material on blue/green light and AlGaInP material on red light through heterogeneous integration and high pixel density through monolithic fabrication approach, demonstrating the feasibility and prospects of high brightness, good color performance, and high-resolution micro-LED micro-displays in future metaverse applications.