In the present study, an existing three-dimensional finite volume computational ocean model(FVCOM) was refined and configured including an algorithm for computing the power density and mean power density at Qiongzhou Strait of China. The refined model was validated with the measured tidal levels and tidal currents at different gauging stations. The model results are in reasonable agreement with the measured data. Based on the modeling results, we assess the resource of the tidal stream energy in the Qiongzhou Strait and discuss the temporal and the spatial distribution of the tidal current energy there. The conclusion is extracted: the higher power density occurs in the middle area of the strait, and lower at both sides. Characteristics of power density such as the maximum possibility speed, maximum power density during the spring tide period and the neap tide period, have the similar distribution. The southeast part and central area of the strait are of rich tidal current energy, where the maximum possibility speed can reach to 4.6 m/s, and the maximum power density of the spring tide period and the neap tide period can reach 5 996 and 467 W/m~2 separately in the surface layer The annual mean power density can reach 819 W/m~2. Statistical length of accumulative time of the velocity exceeding 0.7 m/s is about 4 717 h at local point during a year. The total theoretical tidal current energy resource is approximately189.55 MW and the available exploited energy on present technology condition is 249, 20.2 and 263 GW/a separately by using the methods FLUX, FARM and GC in the Qiongzhou Strait. In the present study, an existing three-dimensional finite volume computational ocean model (FVCOM) was refined and configured including an algorithm for computing the power density and mean power density at Qiongzhou Strait of China. The refined model was validated with the measured tidal levels Based on the modeling results, we assess the resource of the tidal stream energy in the Qiongzhou Strait and discuss the temporal and the spatial distribution of the tidal current energy there. The conclusion is extracted: the higher power density occurs in the middle area of ​​the strait, and lower at both sides. Characteristics of power density such as the maximum likelihood speed, maximum power density during the spring tide period and the neap tide period, have the similar distribution. The southeast part and central area of ​​the strait are of rich tidal current energy, wher e the maximum possible speed can reach to 4.6 m / s, and the maximum power density of the spring tide period and the neap tide period can reach 5 996 and 467 W / m ~ 2 separately in the surface layer The annual mean power density can reach 819 W / m ~ 2. Statistical length of accumulative time of the velocity exceeds 0.7 m / s is about 4 717 h at local point during a year. The total theoretical tidal current energy resource is approximately 189.55 MW and the exploit available energy on present technology condition is 249, 20.2 and 263 GW / a separately by using the methods FLUX, FARM and GC in the Qiongzhou Strait.