To reveal the influence of the wake released from the upstream square cylinder on fluctuating aerodynamic characteristics of the downstream one，wind tunnel tests were carried out to measure the pressure on twin square cylinders，under a uniform inflow condition with a Reynolds number Re of 8.0×104，space ratios P/B of 1.25~5 （where P is the central distance，B is the side length) and various incidence angles of 0° ≤ α ≤ 90°. The variations of fluctuating aerodynamic forces，power spectrums of lift，Strouhal numbers and spanwise aerodynamic correlations with α are investigated considering the multiple space ratios. When P/B < 3，fluctuating forces on the downstream cylinder are roughly smaller than those on a single square cylinder，and they change little at α ≥ 40°. However，when 3 ≤ P/B ≤ 5 and 0° ≤ α ≤ 30°，the fluctuating drag on the downstream cylinder is significantly stronger than that on a single one. The fluctuating forces，power spectrums of lift and spanwise aerodynamic correlations on the downstream cylinder change dramatically when P/B reaches 3. When P/B < 3，vortex shedding from the downstream cylinder is significantly suppressed. When P/B > 3，however，the fluctuating aerodynamic properties of the downstream cylinder become similar to those of a single one.