为得到物面光强分布均匀、能量尽量大的部分相干XeCl准分子激光前端种子光，采用放大自发辐射(ASE)法和散射法开展了前端平滑实验研究。首先，基于一台窄脉冲XeCl准分子激光器，研究了种子光的物面光斑均匀性、能量和发散角随光束口径及物面位置的变化规律。然后，分析了影响种子光参数的因素。最后，进行了验证实验。实验结果显示：ASE法种子光物面光斑不均匀性最小为2.01％，能量为微焦量级，但发散角在水平和竖直方向有较大差别；散射法种子光物面光斑不均匀性最小为1.54％，能量为百纳焦量级，发散角为5.5 mrad，衍射极限倍数处于14~37可调。前端泵浦腔尺寸和入射激光能量、散射板上光斑大小、收集透镜焦距分别是影响两种种子光参数的重要因素。经初级放大器放大后，光束物面光斑不均匀性为2.04％，能量达到8.0 mJ，满足高功率XeCl准分子激光角多路系统建设需求。

The seed beam smoothing experiments were performed to get a smoothing and partial coherence seed by using Amplified Spontaneous Emission(ASE) and scattering methods. The relationship between the uniformity of seed beam intensity distribution,energy,the divergence of seed beam and the beam diameter and postion was investigated based on a short pulse XeCl excimer laser.And then the factors which infulenced the parameters of the seed beam were analysed. Experimental results indicate that the lowest nonuniformity of the seed beam produced by ASE method is 2.01%, and the energy is several μJ. But the horizontal divergence of the seed beam is different from the vertical one. The nonuniformity of the seed beam produced by scattering method is 1.54%, the energy is about one hundred nJ as the divergence is 5.5 mrad, and the laser beam diffraction limited times can be adjusted from 14 to 37. Furthermore,the size of the pumping source influences the divergence of the seed produced by ASE, and the input laser energy, laser diameter on scattering board and the focus of the lens for gathering light influence the parameters of scattering seed. After being amplified, the nonuniformity of the source beam is 2.04%, and the energy is about 8.0 mJ. The results mentioned above show that the seed adapts to the high power XeCl excimer laser system.