In this paper, the frequency response characteristics of a beam with clearance limit constraint are studied by the experimental method and compared with the simulation results at the same time. Experiments are carried out to study the effect of the first order frequency response characteristics by changing the size of the clearance distance and the amplitude of the external excitation. The experimental results show that with the decreasing clearing distance and increasing external excitation amplitude, the first order frequency response of the structure gradually increases, jump range gradually increases, and apparent hardening of the structure occurs. Through the theoretical qualitative analysis, it can also be found that the existence of the clearance in the dynamic governing equation of the system makes the stiffness increase, which induces the frequency change.