Highlights•The electrode layer of TENG was prepared a simple immersing method, without any complex chemical synthesis.•The output voltage of the TENG was almost linearly protentional to the mass of touched steel objects.•The TENG exhibited excellent performance as self-powered flexible sensors to monitor physiological signals.In this work, Ti3C2 MXene supported by cotton fabric was used as electrode layer to construct a novel triboelectric nanogenerator (TENG) as self-powered flexible sensors. The electrode layer was made by immersing cotton fabric in the mixing suspension of Ti3C2 MXene and cellulose nanofibers (CNFs). In the electrode layer, Ti3C2 MXene provides the electrical conductivity and electrical negativity. The fabric substrate provides the strength and flexibility of the electrode layer. The MXene on the surface of electrode layer can lose electrons if it frictionally contacts the friction layer of TENG, silicone rubber. The TENG can produce open-circuit voltage up to 400 V in single-electrode mode during the press-release cycles of a human’s palm. The harvested energy can directly power 32 green light emitting diodes connected in series and charge capacitors. The TENG can sense the mass of touched steel object (2–200 g) with good repeatability and linear relationship. The TENG can be stretched up to 100 % of the original length and can produce different voltage signals according to the bending/folding angles. The TENG exhibits excellent flexibility and sensing performance to be applied as self-powered flexible sensors to monitor various physiological movements of the human body.