The flexible nitrogen-doped reduced graphene oxide/thermoplastic polyurethane (N-rGO/TPU) linear thermosensitive film is synthesized via a straightforward ultrasonic-assisted solution mixing process followed hydrothermal treatment. N-rGO is uniformly dispersed in the TPU film and formed conductive paths, which constructs an excellent three-dimensional conductive network. 2 wt% N-rGO/TPU sensor boasts high precision (0.1℃), excellent sensitivity TCR (temperature coefficient of resistance) of 2.81%/℃ range from 20℃ to 45℃, and robust deformation resilience. Human body temperature measurement is carried out, which can track the changes of human body temperature in real time. This work provides a new idea for the application of graphene materials in flexible temperature sensor.