370nm AlGaInN-based light emitting diodes (LEDs) with SiN in the active layer, fabricated on sapphire substrates by one-time metal organic chemical vapor deposition (MOCVD) have been investigated. Atomic force microscopy and cathodoluminesence results indicated that SiN nano-mask was formed in the active layer, and the degree of compositional indium fluctuation in the active layer of UV-LEDs was enhanced. By using this technique, the output power of the LEDs was improved about 1.3 times than that of the same structure without SiN in the active layer.