Trough the indoor testbed of an engine numerical simulation research , the characteristics of the entire flow field was obtained .We analyzed the physical quantities such as velocity ,static pressure and drawn the entire flow line .Aiming at the modification method of aerodynamic additional drag section method in the indoor testbed ,the velocity and static pressure variation law under different sections are studied ,which provides the basis for the measurement of the measurement points of aerodynamic additional drag section method in the actual test. The measurement and calculation results are obtained through the actual test of a certain engine. The results show that the numerical simulation can clearly simulate the whole field conditions during the test, and obtained the measured inconvenient data. It can supplement the inconvenient measuring positions in the indoor testbed, and obtain the layout of measuring points based on the simulation to meet the requirements of measurement and calculation.