The measurement of nonlinear coefficient of microstructure fiber based on self-phase modulation(SPM)is experimentally demonstrated. A semiconductor laser with 1.6 ps hyperbolic secant shape pulses at a repetition rate of 10 GHz is used as light source. After amplified by the EDFA,the pulses are injected into an 80-m-long dispersion-flattened microstructure fiber. The output spectra of the pulses are broadened due to SPM. By measuring the peak power of the input pulse and the output spectrum,nonlinear coefficient of microstructure fiber can be calculated. This measurement method is simple and accurate,and the error between our experimental result and the measurement result supplied by the fiber producer is within 1%.