A recursive form for the identification of the time-varying state space model and modal parameter of closed-loop system is presented. The approach is derived from the recursive subspace method, and the state space model and modal parameters of closed-loop system are obtained recursively by reconstruct relation of input-output data. In numerical simulations, the parameter identification is studied by considering the cases of sudden change and periodical change of system, respectively. The simulation results show the effectiveness of the proposed approach for identifying state space model and modal parameters of the linear time-varying feedback system.