The high mechanical reliability of a-Si:H TFTs have been fabricated on plastic substrate for flexible display applications. The promising TFT backplane has been successfully applied for AMLCD on colorless polyimide (PI) substrate. The tri-layer of Ti/Al/Ti with 10 μm width are used as scan lines and data lines to replace Cr for stress compensation, and can sustain mechanical bending cycles. The TFTs at 200°C on PI substrate have superior stability with external strain and bending cycles. The redistribution of trap states is analyzed by modeling simulation. The promising a-Si:H TFTs on PI substrate after bending cycles still have superior operation and electrical stress stability and make it possible for AMOLED applications. The Si-based TFTs with high mechanical reliability are highly potential candidate for flexible active-matrix display beyond FPD (flat panel display) generation.