High-performance　THz　polarizers,　as　a　quasi-optical　device　to　manipulate　THz　waves,　are　highly　demanded　for　THz　spectroscopy　and　imaging　applications.　In　this　work,　we　have　employed　the　femtosecond　laser　micro-machining　technique　to　fabricate　freestanding　THz　wire　grid　polarizers　with　two　kinds　of　reinforced　line　structures　which　weaken　the　effects　of　gravity　sagging　and　entanglement　of　long　free　wires,　thus　enabling　large-scale　processing.　The　effect　of　the　reinforced　lines　on　the　polarizers　were　simulated　by　the　Finite-Difference　Time-Domain　(FDTD)　method,　and　the　performances　of　the　polarizer　were　characterized　by　THz　time-domain　spectroscopy　and　compared　with　that　of　a　commercial　wire　gird　polarizer.　The　calculated　transmittance　is　in　good　agreement　with　the　FDTD　results.　The　degree　of　polarization　and　the　extinction　ratio　of　the　polarizer　with　discontinuous　reinforced　lines　are　better　than　those　of　a　commercial　wire　grid　polarizer.　©　2020　Elsevier　GmbH