21-day in-situ ADCP current and CTD data from an anchored observational station by R/V Shiyan 3 are used to investigate the characteristics of internal tide in the northern South China Sea continental slope. The results show that tide and internal tide are both mixed type in the observed region and dominated by diurnals; the maximum internal tidal major axes of K1, O1 were largest and reached 11 cm/s, 10 cm/s, respectively, and their current vectors rotate anticlockwise. The 300 m-deep internal tide presents obvious quasi-diurnal oscillation and its average amplitude reaches 50 m. Furthermore, internal tide carried high energy; in the upper layers above 140 m, the kinetic energy of internal tides accounts for 15%-37% of overall kinetic energy, most of internal tide energy concentrates around the thermocline. 21-day in-situ ADCP current and CTD data from an anchored observational station by R / V Shiyan 3 are used to investigate the characteristics of internal tide in the northern South China Sea continental slope. The results show that tide and internal tide are both mixed type in the observed region and dominated by diurnals; the maximum internal tidal major axes of K1, O1 were largest and reached 11 cm / s, 10 cm / s, respectively, and their current vectors rotate anticlockwise. The 300 m-deep internal In addition, the internal tide carried high energy; in the upper layers above 140 m, the kinetic energy of internal tides accounts for 15% -37% of overall kinetic energy, most of internal tide energy concentrates around the thermocline.