Terahertz wire-grid polarizer and terahertz band-stop filter have been fabricated on polyimide substrate by laser inducing and non-electrolytic plating with copper. The performance of the fabricated devices is measured using a terahertz time-domain spectroscopy. Test results demonstrate that the high extinction ratio of the fabricated polarizer is better than 20 dB from 0.2 THz to 1.5 THz, and three different central frequencies are 0.41, 1.07, 1.47 THz for the Jerusalem cross band-stop filter. The experimental results are in good agreement with finite-difference time-domain simulations. The results demonstrate that the laser induced and non-electrolytic plating with copper is a simple, effective, and flexible way to fabricate terahertz devices on polyimide substrates.