In the paper, the demonstration of a high-power LD-pumped Yb, Na:CaF2 femtosecond laser is presented, which the cavity is optimized concerning the numerical simulation for the thermal lens effect. With a 2% output coupler, a continuous-wave mode-locked pulse train with a pulsewidth of 190 fs, the average output power of 503 mW, the center wavelength at 1034 nm and a repetition frequency of 82.4 MHz is obtained under the absorbed pump power of 7.8 W. If other forms of output are recorded, such as the reflection of the crystal surface, the total output power is 905 mW.