This paper presented an experimental investigation on the dynamic characteristic of nested compression spring gas foil bearings（NSFBs）. A test rig was built to test the dynamic characteristic of the NSFB. Impact load tests with stationary rotor and rotating rotor（24.00 kr/min） were conducted，respectively. The dynamic stiffness and equivalent viscous damping coefficients of the studied bearing were extracted from the results of impact load tests. Bearings with different spring numbers were tested and their dynamic coefficient were compared. Static load tests were conducted to measure the real clearance of the test bearings after assembling. And then the diameter of the rotor in the impact load tests was calculated based on the tested real bearing clearance to confirm that the nominal clearance for the test bearings with different spring numbers are the same under the impact loads. For both the tests with stationary rotor and rotating rotor，the direct stiffness coefficients，direct equivalent viscous coefficients，and loss factor increasd as the spring number increased. However，the direct stiffness and equivalent viscous coefficients for the test with rotating rotor were smaller than the results of the test with stationary rotor.