Differential optical absorption spectroscopy (DOAS) is a spectroscopic technique which can be used to monitor many kinds of air pollutants simultaneously. In th is paper, in situ measurement of nitrous acid and retrieval of aerosol parameter s in a fixed wavelength range (307 nm—380 nm) were performed with DOAS system d eveloped by our laboratory. The measurements of HONO concentration were more acc urate using the NO2 standard absorption cross section measured by our selves a nd aerosol parameters were retrieved successfully in a shorter wavelength range.