In order to study the complex fluctuating wind environment of Dabancheng wind area located in Urumqi, Xinjiang, the measured wind speed data was used to analyze and fit the downwind fluctuating wind power spectrum of the wind area. The results show that the error in fitting the relationship between mean wind speed and turbulence intensity in mountain canyon terrain with an inverse proportional function is small. The integral scale distribution of topographic turbulence in mountain canyons is more discrete, but overall increases with the increase of mean wind speed. The Kaimal modified spectrum considering terrain coefficient can represent the measured spectrum better in Energy-containing Range and Inertial Subrange, and the three-parameter fitting in Dissipation Range is chosen to describe the measured wind spectrum well. The transition function is used to describe the power spectrum of the contact region between Inertial Subrange and Dissipation Range, and the fitting effect is better. It is concluded that Dabancheng wind area has special downwind fluctuating wind characteristics, and the function model composed of modified spectral and fitted spectral segments can be used to characterize the downwind pulsating wind power spectrum in this wind area.