In the modern cosmopolitan world, flexible sensors are essential components of the intelligence and information industry. We analyze the latest advancement and improvement of research into the pliable or flexible material based carbon nanotubes sensors. Linear cables kind and flexible materials based on carbon nanotubes are used for developing intelligent flexible equipment for applications in electronics, artificial skin, biomedicine, robotics, energy, healthcare products and most importantly for sensing hazardous gases. In the present analysis, we outlined the development of flexible sensing platforms based on carbon nanotubes and polymers for sensing various environmental polluting gases such as CO ₂ , H ₂ S and NH ₃ . In addition, we also discussed the device structure, materials and fabrication techniques for developing flexible sensors. The conclusion exhibits the viewpoint and the challenges faced by the materials and methods of the flexible sensor.