The rapid development of wearable electronics has led to an enormous demand for power sources that are wearable, small-scale, flexible and compatible. In this work, poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS) as the liquid electrode and silicone rubber as the triboelectric/encapsulation layer were introduced to design a stretchable PEDOT:PSS liquid electrode-based triboelectric nanogenerator (PL-TENG). The elastic silicone rubber and PEDOT:PSS liquid electrode with a special macromolecular structure endowed PL-TENG with extraordinary flexibility and conductivity simultaneously. Working under the single-electrode mode with different motion frequencies from 0.5 to 2.5 Hz, PL-TENG generated open-circuit voltage of 265 V, short-circuit current of 24.9 μA and short-circuit charge quantity of 85 nC. The output performances still maintained the original values after washing in saline, storing for one month and stretching 10 000 times. At the same time, PL-TENG could also produce stable electrical outputs even when deformed into a variety of shapes including stretching in different directions, bending and twisting. All of these features demonstrated the excellent resistance of PL-TENG to sweat, time and deformation. When attached to a human body, PL-TENG could provide a sufficiently stable power output to drive wearable electronics sustainably.