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The wind field has a significant impact on the spread speed, fire distribution and operational safety of forest and grassland fires. This study aims to explore the application value and practical effect of Doppler wind laser radar at the rescue site of forest and grassland fires. Based on the observation data of Doppler wind laser radar at the “3·15” forest fire rescue site in Yajiang, Sichuan, in 2024, this paper first verifies the accuracy of the three-dimensional wind field inversion using the three-dimensional variational method under complex terrain conditions with the multi-elevation plane position indicator (PPI) data of the scanning wind laser radar. On this basis, the wind field information observed at three fire points in Yajiang by the PPI scanning mode of the wind laser radar is used to conduct a preliminary analysis of the spread of the fire and the horizontal diffusion of smoke. At the same time, the vertical wind profile of the fire scene is retrieved through the Doppler beam swinging (DBS) mode data, and the vertical atmospheric motion of the fire scene is analysed in combination with the extinction coefficient. The results show that the vertical wind field retrieved by the DBS mode is used as the background field of the three-dimensional variational method. The three-dimensional wind field retrieved under complex terrain conditions has high accuracy, and the average deviations of wind speed and wind direction are -2.51% and 3.92%, respectively. The wind direction in the fire determines the direction of fire spread and smoke propagation. The vertical wind profile of the fire scene retrieved through the DBS mode captures the low-altitude jet and momentum transfer phenomenon that may cause sudden changes in fire intensity, and the vertical transport of smoke in the fire can be further analysed in combination with the extinction coefficient. The application of Doppler wind laser radar in wind field monitoring at the scene of forest and grassland fires is of great significance for improving the scientific level of command and management at the rescue site.