介绍了国外四频差动激光陀螺（FMDLG）的发展历程和应用现状。通过对FMDLG相关研究资料的调研，归纳了提高FMDLG性能的关键，包括基础理论的研究、基础工艺的提高、腔体的优化设计、电子系统设计和误差补偿技术。概述了国内的FMDLG研制历史和现状，结合自身研制经历，给出了FMDLG需要解决的若干问题。

The development history, key techniques and applications of four-mode differential laser gyros (FMDLGs) are summarized so as to provide some reference for domestic development of FMDLG. The keys to improve the performance of FMDLG are concluded according to investigation on materials related to FMDLG, including fundamental research, technical improvement, optimization design for cavity, electronic system design and error compensation technique. In order to fully realize the potentials of FMDLG, each key aspect should be taken into account elaborately.