In response to the needs of micro-displays for red LEDs with high external quantum efficiency, low operating current, and stable spectral wavelength,a Micro-RCLED that combines resonant cavity light-emitting diodes with AlAs lateral oxidation technology is realized. The device changes the spatial distribution of the spontaneous radiation field in the active region by a resonant cavity to concentrate more light within the light extraction angle to improve the light extraction efficiency, meanwhile, the resonant cavity is also beneficial to deminish the shift of the optical spectrum. The lateral current confinement to the AlAs oxide aperture can not only decreasing the Shockley-Read-Hall non-radiative recombination due to the sidewalls defects, but also reducing the leakage current so to improve the radiative recombination efficiency. In addition, the diameter of the light exit aperture of the P electrode is larger than that of the AlAs oxidation aperture, so that the absorption of the outgoing light by the P electrode can be effectively avoided. The 655 nm Micro-RCLED with 3 units parallel connected is fabricated, in which each unit has an exit aperture of 17 μm diameter. Fitting result of IdV/dI-I shows a reasonable 120 Ω series resistance. The output optical power of the device at 1 mA is 0.21 mW, the external quantum efficiency is greater than 10%, and a single unit can be lighted up at an injection current lower than 1 μA. In addition, when the working current density changes by 12.5 times, the peak wavelength only increases by 1.5 nm, and the full width at half maximum of the spectrum increases just 0.33 nm.