Bu using a regenerative amplifier with folded standing wave resonator, laser diode array (LDA) pumped regenerative amplification of single longitudinal mode laser pulse with high stability is realized. The build up process of single longitudinal mode laser pulse from injection to regenerative amplification is stuided in detail. The total gain of 1.2×10 7 is obtained in the regenerative amplification. The single pass net gain is 1.5, and the dumped energy of single pulse is 1.2 mJ.