Numerical simulation is used to study the effect of pump wavelength on mid-infrared supercontinuum generation when femtosecond pulse is transmitted in As2S3 suspended-core microstructure optical fiber. The transmission characteristics and evolution process of femtosecond pulse with different pump wavelengths in As2S3 suspended-core microstructure optical fiber are analyzed by using split-step Fourier method to solve the generalized nonlinear Schrdinger equation numerically. The analytical results demonstrate that the flatter and wider mid-infrared supercontinuum of 1-7 μm can be obtained when the pump wavelength is 2300 nm, locating in anomalous dispersion region and closing to zero dispersion wavelength. And the wider mid-infrared supercontinuum of 1-7.5 μm can be obtained when the pump wavelength is 2500 nm, locating in anomalous dispersion region and keeping away from zero dispersion wavelength. But the flatness of mid-infrared supercontinuum with 2500 nm is slightly worse. This study has a significant reference value for selecting pump wavelength and optimizing mid-infrared supercontinuum.