In order to study the influence of pretension detuning on the natural frequency of a distributed tierod rotor with a large number of joint surfaces, the influence of pretension detuning on the natural frequency was studied by combining experimental analysis with finite element method.The detuning finite element model of the tierod rotor considering the contact stiffness of the joint surface was established and modal analysis was carried out. A test bed for natural frequency measurement of distributed tierod rotor was designed and built to measure the first-order natural frequency of the tierod rotor under different detuning conditions and verify the accuracy of the finite element model.The simulation and test results show that the natural frequency decreases with the increase of the number of detuning rods when the pretightening detuning of the rod rotor is same, which verifies the accuracy of the dynamic model of the detuning rod fastening rotor.