This paper investigates the design of finite-time hybrid bumpless transfer fault detection filter (FDF) for switched linear systems with all subsystems unstable under mode-dependent interval dwell time (MDIDT) switching. Firstly, in order to improve the transient performance of the fault detection system, a hybrid bumpless transfer performance description is proposed, which directly limits the total amplitude of residual and rate bumps at switching instants. Then, by dividing the dwell time interval into segments,a less conservative time-varying discretized Lyapunov function is constructed, and sufficient conditions for ensuring the finite-time stability and finite-time H∞ performance of the augmented system under MDIDT switching are obtained. On this basis, the design conditions of the finite-time hybrid bumpless transfer FDF are given. Finally, a numerical example is given to verify the effectiveness and superiority of the proposed method.