Q-switched fiber laser was demonstrated by using tungsten disulfide (WS2), which was deposited onto D-shaped fiber as a passive saturable absorber (SA) to modulate the loss inside the laser cavity. The SA was produced by repeatedly dropping and drying the WS2 solution onto side-polished fiber to form a nanosheets layer. The SA is inserted into the ring laser cavity configured with a 2.4 m long Erbium-doped fiber as the gain medium to generate Q-switching pulses train operating at 1557.9 nm. The Q-switched laser produced a pulse train, which the repetition rate is tunable from 77.2 to 108.9 kHz as the pump power is increased from 84.0 to 182.9 mW. The minimum pulse width of 3.25 µs and the maximum pulse energy of 14.6 nJ was obtained at 182.9 mW pump power. The generated Q-switching pulses are stable and thus it is suitable for use in many practical applications.