The peak power of ultra-short picosecond pulses is high, and the realization of the large energy output is difficult. The single pulse is divided into multiple adjacent pulses, which can increase the total energy of the pulse envelope and increase the laser output power. A single-channel mode-locked picosecond seed laser output with an optical-to-optical conversion efficiency of 39.3% is designed and obtained, and a method of dividing a single pulse into multiple pulses is proposed. By using Bragg volume grating (VBG) pulse broadening, multiple pulse generation, regeneration amplification, traveling wave amplification, and frequency conversion, a laser output at 532 nm with four pulses, 1 ns pulse spacing, 10 W output power, 10 mJ pulse envelope energy, 100 ps pulse width of the single pulse, 1.67 beam quality, and 1 kHz repetition frequency is obtained. Through the thermal lens effect pumped by the laser module, the laser output emission angle can be adjusted continuously and accurately by adjusting the pump current, and the minimum divergence angle is 0.2 mrad. The designed method is applied to the space laser ranging station of Shanghai Observatory to carry out the ranging of multiple space debris, and the ranging accuracy is 16.44 cm. The results show that multiple pulses can increase the total laser output energy and laser output power, which provides an effective technical way to improve the ability of space debris laser ranging detection.