利用相干衍射辐射(CDR)光学自相关技术在线无阻拦频域测量超短电子束团的长度是当前国际束测领域的研究热点.文中分析和数值计算了利用上海应用物理研究所(SINAP)飞秒电子束装置提供的超短电子束团产生的宽带连续强CDR,介绍了超短电子束团长度测量的实验原理和装置示意,并研究了分束器对束团长度测量的影响.结果表明,该束团可直接用于产生覆盖远红外至毫米波段的宽带连续强CDR;辐射能量主要集中在轴线附近,宏脉冲辐射能量可达毫焦耳量级;利用光学自相关技术研制的远红外Michelson干涉仪和Golay探测仪组成束团长度测量系统,通过实验测量CDR干涉图FWHM可近似求得超短束团长度;干涉图借助傅立叶变换光谱法,可推算求得束团电子密度分布的信息. It is a hot topic in the field of international beam measurement to measure the length of the ultrashort electron bunch in the unobstructed frequency domain by using the optical autocorrelation technique of coherent diffractive radiation (CDR) .In this paper, we analyze and numerically calculate the SINAP using the Shanghai Institute of Applied Physics Second electron beam device provided by the short continuous electron beam generated broadband continuous strong CDR, introduces the experimental principle and device short electron beam length measurement schematic and beam splitter length of the study measured the impact of the results show , Which can be directly used to generate broadband continuous strong CDRs covering the far infrared to the millimeter wave band. The radiant energy mainly concentrates near the axis and the energy of the macro pulsed radiation can reach millijoules. The far infrared Michelson developed by optical autocorrelation Interferometer and Golay detector to form a bunch length measuring system. The FWHM of the CDR interference map can be obtained by experiment to obtain the length of the ultrashort bunch. The interferogram can be used to calculate the electron density distribution of the bunch by Fourier transform spectroscopy.