A fully differential line driver, with high linearity is presented，which is applied in narrowband Power Line Carrier Communication(PLCC). The proposed configuration includes a preamplifier with programmable gain and a power output stage. The preamplifier features an adjustable output swing, and the static power consumption can be switched by output stage according to power detection circuit. The proposed line driver is deigned based on Semiconductor Manufacturing International Corporation(SMIC) 180 nm Complementary Metal Oxide Semiconductor(CMOS) technology. Post-layout simulated results show that the maximum current driving capacity is up to 660 mA and the Total Harmonic Distortion(THD) is less than -60 dB when peak-to-peak value of output swing is 4 V, which meets the requirement of narrowband power line carrier communication.