对近红外探测器PDA400的响应特性进行了测试，并就探测器响应特性对连续波腔衰荡法腔损耗测量结果的影响进行了理论分析和实验研究。通过求得的探测器线性响应情况下的响应函数，推导出衰荡信号输入时探测器的输出信号线形，发现原本应呈单指数衰减的信号变为了双指数衰减。根据探测器响应时间的测试结果，针对PDA400探测器增益设置为20 dB,40 dB两种典型情况下的衰荡信号拟合进行了研究。提出了针对不同探测器增益设置(不同响应时间)时的衰荡信号数据处理方式，并进行实验验证，消弱了探测器响应特征对腔损耗测量结果的影响。最后就探测器非线性响应情况下的衰荡数据处理作了讨论。

The response characteristic of near infrared detector PDA400 was measured, then the theoretical analysis and experimental study,which focused on the relation between detector's response characteristic and metrical result of continuous-wave cavity ring down technique, were both carried on. With the linear response function, the output signal of PDA400 was deducted when ring down signal was used as input.In this case,analusis shows that the signal shape of PDA400 has turned from single to double exponential function. After the response times of PDA400 in different gains were measured, the fitting method of ring down signal in two typical detector's gain(20 dB and 40 dB) was studied, and two kinds of methods were proposed and tested with experiments. Furthermore, when considering detector's nonlinear response, the method of data processing is discussed too.