Flexible electronics are possible alternative for portable consumer applications with many advantages. However, the circuit design for flexible electronics is still challenging, especially for sensitive analog circuits. Significant parameter variations and bending effects of flexible TFTs further increase the difficulties for circuit designers. In this paper, an automatic circuit sizing technique is proposed for the analog circuits with flexible TFTs. The process variation and bending effects of flexible TFTs are considered simultaneously in the optimization flow. As shown in the experimental results, the proposed approach can further improve the design yield and significantly reduce the design overhead.