According to the working principle of Czerny-Turner structure spectrometer, to make the system miniature and portable as specific design objectives, a crossed-asymmetric Czerny-Turner spectrometer with spectral range of 200 nm~900 nm was designed. Based on the spectrometer resolution and spectral range, we could determine the general structure. Then the primary aberration was used to optimize the initial structure, first proposed combining the spherical aberration constraints and aperture surface selection and designed process to determine the collimating mirror aperture, initial grating size and focusing lens aperture of the center wavelength, and then combined with the constraints of coma to calculate the spherical mirror off-axis angle, and based on geometric optics to determine the initial focus lens aperture. The imaging simulation, analysis and optimization for optical system were carried out with optical design program ZEMAX. The spectrum of mercury-argon light and the spectrum of halogen light are measured by our self-developed spectrometer. The results of analysis demonstrated that the optical system achieved central wavelength resolution less than 1 nm, edge wavelength resolution less than 1.5 nm, in conditions of the slit width is 25 μm, the groove spacing is 1.667 μm/line.