A chemiluminescent method with silver nanoparticles for determination of L-alanine has been presented. The chemilumiscence intensity was further enhanced by silver nanoparticles in the luminol system by its catalytic role. The silver nanoparticles enhanced chemiluminescent method is applicable for the determination of an amino acid such as alanine. When alanine was introduced to the luminol system with silver nanoparticles, chemiluminescence intensity was reduced with the concentration of the added alanine. The effects of pH, concentrations of luminol, hydrogen peroxide and silver nanoparticles on the chemiluminescence intensity were investigated. The calibration curve for L-alanine was linear over the range from 6.60×10^(-8) M to 4.00×10^(-7) M, coefficient of correlation was 0.996 and detection limit was 3.5×10^(-9) M under the optimal conditions of 4.0×10^(-3) M, 4.0×10^(-2) M, 4.0×10^(-4) M, 12.8 for the concentration of luminol, H2O2, silver nanoparticles and pH, respectively.