A femtosecond Ti:sapphire chirped pulse amplifier with multipass amplification was developed in this paper, new concepts on overcoming gainnarrowing and enhancing amplification efficience are also introduced. Pulses of 25fs duration with 36mJ energy have been produced at repetition rates of 10Hz only under 290mJ doubled frequency Nd:YAG laser pump, which corresponds to 1.4TW peak power.