法布里-珀罗(F-P)干涉仪是具有重要科研和实用价值的光学仪器，能广泛应用于光学鉴频、锁频以及光谱超精细结构的测量研究。然而，在实际应用中干涉仪的频谱特性将受到诸多因素的影响。从入射光束发散角、入射光频谱、干涉仪平板吸收损耗、平板表面缺陷和不平行度等因素对F-P干涉仪频谱特性的影响做了深入的研究。在考虑了上述诸多实际因素情况下，理论上导出了F-P干涉仪的透射频谱函数的一般表达式；定量给出了由发散角引起的透射频谱整体平移量；提出了等效发射激光谱宽的概念，将入射光束发散角、入射光频谱、干涉仪平板表面缺陷和不平行度等对透射频谱的展宽效应合并处理，给出了定量的等效关系式。这些结果可为法布里-珀罗干涉仪的设计与应用提供借鉴。

Fabry-Perot interferometer(FPI) is an optical instrument with important scientific and practical value, which can be widely used in optical frequency discrimination, optical frequency locking and spectral measurements of the hyperfine structure. However, in practical applications, the spectral characteristics of the interferometer are affected by many factors. In this article, the impact of several factors on Fabry-Perot interferometer spectral properties, such as the beam divergence angle, the spectrum of the incident light, the absorption loss, surface defects and non-parallelism of the interferometer two plates were studied in depth. Considering the above practical factors, a general expression for the transmission spectrum function of F-P interferometer was derived theoretically. The overall shift of the transmission spectrum caused by the divergence angle was given quantitatively. The concept of equivalent spectral width of the emitting laser was proposed, the broadening effects on the transmittance spectrum of the incident beam divergence angle, the spectrum of the incident light, surface defects and non-parallelism of the interferometer two plates were all considered, and their quantitative equivalent formula was given. These results would provide a reference for the design and application of Fabry-Perot interferometer.