In order to study the spatial correlation of the along-wind fluctuating wind load of lattice tower, two segmental models of a typical lattice tower were selected, and two high frequency force balance technologies were employed. The time histories of the base shear and bending moment for the segmental models considering different horizontal and vertical distances between them were synchronously obtained in the wind tunnel test. Based on the extensive analysis of the obtained data, the coherence function formulas of the along-wind fluctuating wind load on the lattice tower model were obtained. The results show that the coherence functions of the along-wind fluctuating wind load on the lattice tower are related to the frequency, horizontal distance, and vertical distance. There is a certain deviation between the deduced coherence functions obtained by this experiment and the existing coherence functions of longitudinal wind speed or wind load of high-rise buildings. Finally, the least square method was used to fit an empirical formula of the coherence functions of the along-wind fluctuating wind load on the lattice tower. The experimental results are in good agreement with the empirical formula, which can provide a useful reference for the calculation of the wind load and wind-induced response of lattice towers.