We have implemented a femtosecond laser tweezers,and the stable optical trapping of human red blood cells(RBC) was observed.A homemade Kerr-lens mode-locked(ML) Ti:sapphire laser that delivers 40 fs pulses at 810 nm with a 100 MHz repetition rate was used as the light source.We measured the optical trapping capability and Q-values of the femtosecond laser tweezers in comparison with CW laser tweezers.From the experiments,we can see femtosecond laser tweezers are just as effective as CW laser tweezers on optical trapping of biological cells.The technology of optical tweezers integrated with characteristics of femtosecond pulses has a good future.