A composite method is proposed to correct the astigmatism, which aims at the problem that the astigmatism of the wide band of the Czerny-Turner structure spectrometer is hard to correct at the same time. With the new approach, when the ability of the first-order astigmatism correction reaches the limitation on wide broadband wavelength, the astigmatism opposite trend of added cylindrical lens is used to further compensate the residual astigmatism in the optical system. The astigmatism compensation formula on marginal waveband of with composite method is deduced. With the composite method, an anastigmatic Czerny-Turner structure on near-infrared waveband ranging from 900 nm to 1700 nm is designed. The simulation results of Zemax show that the root-mean-square (RMS) value of full-band and full fields of view is less than 14 μm, modulation transmission function (MTF) is higher than 0.7, and the spectral resolution is 1.5 nm at all wavelengths. The composite method achieves simultaneous correction of astigmatism at near-infrared 800 nm wide waveband, which can avoid energy transverse spread. The method can be applied in structure design at other wavelengths, and it is meaningful for designing broadband anastigmatic optical systems.