为降低高功率激光系统中连续相位板(CPP)后续元件的强激光损伤风险，综合考虑入射光强调制、干涉及衍射作用等多种影响因素，建立了CPP近场计算分析模型，模拟和分析了这些因素对CPP后的近场均匀性的影响。理论分析结果表明：CPP后的光束近场均匀性主要受入射光调制、CPP表面剩余反射率和衍射传输距离的影响；当入射光束质量较差时,CPP后的近场均匀性主要由入射光束质量决定，CPP剩余反射率和衍射传输距离对近场均匀性影响相对较小；但当光束质量比较理想时，干涉和衍射作用会破坏CPP的近场均匀性，衍射传输距离影响尤为突出。

A theoretical model for calculating the near field caused by continuous phase plates(CPP) applied in high-power laser system is built up for decreasing the laser induced damage probability of the elements behind CPP. The distribution of near field caused by CPP is calculated and analysed using this model, and the effect on the uniformity of the near field caused by the intensity modulation of input beam, interference and diffraction from CPP is analysed. The simulative and analytical results show that the interference ,the diffraction and the input beam quality affect the uniformity of the near field, and the input beam affect the beam quality of CPP more severely than the interference and diffraction when the beam quality is bad, but the interference and diffraction will decrease the uniformity of near field if the quality is perfect, and the diffraction will decrease the uniformity of the near field more severely than the interference.