GaN-based Micro-LEDs have shown great potential in various filed, such as solid-state lighting, display, sensor, visible light communication and multifunctional devices. The performance of Micro-LEDs in various operating environment drew enormous attention recently. We report high performance Micro-LEDs on sapphire substrate with device size scaling to 30um and ultra-high current density of 100A/cm2 under applied bias of 4V. The Micro-LED devices can keep comparable performance after extreme environment test with an emission wavelength of 460nm. We also proposed three method to improve ambient contrast ratio including optical method, anti-reflection film and optimized device structure.