Research on the types of urban terrain combination and the influence of terrain on wind field is helpful to understand the mechanism of urban wind field and optimize its ecological environment. Taking the main urban area of Guangzhou with dense high-rise buildings as an example, on the basis of determining the urban macro-terrain type, the air duct is identified based on the low cost path (LCP), and the wind environment quality is evaluated. The results show that (1) the urban terrain is briefly divided into 4 first-grade terrains and 11 second-grade terrains. (2) According to the standard that the intersection angle between LCP path and prevailing wind does not exceed 22.5°, the ventilation path is screened and determined as the wind duct. Base on the density and frequency of LCP grid, combined with wind speed and wind frequency under different wind directions, the wind environment type and spatial distribution were evaluated and analyzed. (3) According to the configuration of natural and urban topography, the environmental quality of north wind is much higher than that of northwest wind and east wind. The east wind has the lowest wind frequency and wind speed, so its ventilation condition is poor. (4) The results show that the Pearl River waterway is the widest and the best wind passage in the city under three wind directions. The regional wind tunnel and the section with better wind environment are concentrated on the main road parallel to the prevailing wind direction, but the most of them are similar to the north-south direction. Because the height of Guangzhou urban terrain decreases outward with the Peak Clusters of Pearl River New Town as the center, the ventilation of the periphery of the main urban area dominated by low-lying terrain is better than that of the central area. In particular, the old urban area with Peak Clusters and network platform in New Pearl River City has poor ventilation environment. Based on the LCP evaluation results, this paper requires mutual verification of different technical routes in order to improve and optimize them continuously.