This paper characterizes the pressure drop of incompressible airflow when passing by a metal mesh screen which acts as a protection from sucking foreign solid matters before the gas turbine compressor. The wire diameter is 1.2mm and the mesh number is 3. Two experiments are conducted in different time period of a day to guarantee the experimental repeatability. The experimental data are used in regression analysis to obtain a quadratic correlation between the pressure drop across the screen and the fluid velocity. Numerical simulations are utilized to investigate detailed velocity and pressure fields around the wires and the Standard k-ε turbulence model is used. The results show that the fluid suffers from around 140Pa and 250Pa total pressure drop at the velocity of 20m/s and 30m/s respectively. The pressure closely upstream of the wires is as high as 4 times of the inlet flow level, while wide negative pressure regions are observed downstream of the wires resulting from fluid stagnation, reverse flow and recirculation. The empirical correlation obtained in the paper has a high confidence level and can be used in calculating the overall pressure drop of the gas turbine air intake system.