Abstract: Abstract: Research goal:12 native amino acids were separated and determined in 18 minutes by high performance capillary electrophoresis with UV detection.Method: the time is 30s ,the height is 25 cm;running voltage is 15 kV; bouncy silica 75 μm , buffer 10 mmol/L sodium tetraborate，30 mmol/LSDS,and 0.1 mmol/L Urea, pH =11.40. Conclusion:The conditions of separation and determination were gravitation sampling.