On the basis of calculation and analysis on femtosecond amplification gain saturation and femtosecond pulse stretching, we believe it is possible to achieve moderate energy femtosecond regenerative amplification without stretcher if the amplifying cavity parameters is optimized and the pumping pulse energy is changed. According to the conclusion, applying low pumping energy and Ti:sapphire off-focusing technique to the amplifier, we do the experiment about high repetition rate femtosecond Ti:sapphire regenerative amplification and compressing without the stretcher. The femtosecond amplified pulse of perfect beam quality is obtained. The energy of amplified pulse is more than 100μJ.The amplified pulse repetition is 1kHz. The spectrum FWHM is 7.7nm.After the compressing,the pulsewidth is 500fs.