The evolution of haze and its synoptic characteristics in Guilin are stuied by means of the 50year observation data from the urban station and four the surrounding stations, with relative humidity and visibility to proofread the haze days in records, so to determine haze days objectively. Through analyzing the basic weather situation leading to haze formation, maintenance, and dissipation respectively, the haze weather characteristics are studied to provide a basis for haze weather forecast. The results indicate that haze in Guilin presents an obvious increasing trend from the beginning of the 21st century, and haze happens more frequently in winter than in summer. The basic synoptic features of haze in Guilin are: there is no wind or weak wind (≤3.0 m/s) on the ground; the atmospheric is dry (relative humidity ≤70%); there is a temperature inversion near the surface; ground temperature changes are positive and the humidity changes are negative. The corresponding weather situations are: straight flow or weak ridge at high altitudes, weak high pressure or strain field on the ground, subtropical high pressure belt, warm sector before front, near surface layer inversion, stable upper atmosphere. According to the weather situation analysis, the forecast platform of Guilin haze weather was build, which received good results in haze forecasting.