A novel reconfigurable optical add-drop multiplexer (ROADM) based on narrowband thin-film filter is proposed. The ROADM consists of three single-fiber collimators, a pair of three-port optical circulators, a pair of mirrors and one particularly designed angle-tuned narrowband multiple cavities filter. By control a stepping motor to change the incident angle of the thin-film filter, the ROADM can add or drop a selective wavelength. The characteristics of the ROADM are studied experimentally, and especially the crosstalk is analyzed and calculated in detail. In the experiment, the channel isolation is more than 34 dB and its tunable range is over 26 nm, which coincide with the results of theoretical calculation. The RAODM has many advantages such as simple structure, wide tunable range, high isolation, low polarization-dependent loss, low cost and so on. It can be widely used in practical DWDM system.