提出一种测量晶体光损伤阈值的新方法 ,即确定激光横向功率密度的空间分布 ,利用晶体的激光损伤斑点半径 ,直接计算出晶体光损伤阈值 ,并给出入射激光为高斯光束时晶体损伤阈值与其损斑半径的关系。以提拉法生长的掺镁铌酸锂 (MgO∶LiNbO3 )晶体为研究对象 ,用该方法测量其损伤阈值 ,得到了定量结果且所得数据与文献已报道的规律相符。分析得出同样激光条件下 ,损斑半径越大的晶体其光损伤阈值越小的结论 ,指出该方法同样适用于其他晶体或非高斯光束条件下光损伤阈值的测量并对具体作法进行了讨论。该测量方法弥补了常用测量方法只能定性或半定量的不足 ,可用于晶体抗光损伤阈值的精确测量 A new method to measure the damage threshold of crystal is proposed, which is to determine the spatial distribution of lateral laser power density. The damage threshold of crystal is directly calculated by using laser damage spot radius. The damage threshold of crystal when the incident laser is Gaussian And its damage spot radius relationship. The crystal growth of magnesium doped niobate (MgO: LiNbO3) was investigated by the Czochralski method. The damage threshold was measured by this method. The quantitative results were obtained and the data obtained were consistent with those reported in the literature. It is concluded that the smaller the damage threshold of the crystal with larger damage radius under the same laser condition is, the conclusion is drawn that this method is also suitable for the measurement of light damage threshold under the condition of other crystals or non-Gaussian beams and the specific method is discussed . The measurement method to make up for the commonly used measurement methods can only be qualitative or semi-quantitative deficiencies, can be used for accurate measurement of crystal light damage threshold