High-performance 400 nm violet InGaN multi-quantum-wells light-emitting diodes (LED) with p-AlGaN electron blocking layer were fabricated on sapphire substrate by metal organic chemical vapor deposition technique.Different conditions were chosen to grow p-AlGaN electron blocking layers in three violet LEDs.Using 10 pairs of p-AlGaN/GaN super lattice electron blocking layer,the output power have been greatly improved.A LED with an output power of 21 mW at an injection current of 20 mA was achieved.In additional,the LED also show an almost linear I-L characteristics at high injection current and uniform intensity mapping on LED chip surface.