To enable a spectrophotometer to achieve high resolution across a broad spectral range, an optical system utilizing an asymmetric Czerny-Turner configuration is developed, featuring a rotating grating. This system's design adheres to the working principle of the spectrophotometer and the theory of geometric aberration while accounting for the effects on central and edge wavelengths. The characteristic and structural parameters of each optical component in the spectroscopic system are accurately determined. Focusing on spectral resolution, the optical system is simulated and optimized using Zemax software to determine the optimal optical path structure. The multi-configuration is used to simulate the grating rotation, thereby allowing for the scanning of wide wavelength bands. The simulations indicate that the system's resolution consistently surpasses 0.1 nm within the 300?1000 nm spectral range. The experimental setup confirms that the spectrophotometer's spectral resolution attains a technical specification of 0.1 nm. Consequently, The designed spectrophotometer optical system serves as a valuable reference for the development of high-resolution spectroscopic instruments capable of operating across a broad spectrum.