为解决硬X射线自由电子激光装置难以提供皮秒至纳秒区间时间分辨的问题，提出了面向目前在建的上海硬X射线自由电子激光装置分束延迟的系统设计。采用基于晶体衍射的延迟方法设计分束延迟光学系统，计算了延迟时间范围，模拟了系统光通量，搭建了一台样机并进行了光路对准实验。该设计采用空间分光方式，将入射脉冲分为两个部分，并通过路程差在二者之间引入时间延迟，具体的原理样机设计适用于光子能量在7~11 keV范围，最多能实现-15.4~503.3 ps的时间延迟。使用Shadow模拟了样机设计的光通量，两个分支光通量分别为33.54%和33.64%，符合1∶1的设计目标。使用绿光激光进行了样机的光路对准实验，证明该样机能使空间分光后的两束光重新复合，为后续X射线验证实验提供基础。该设计具有空间尺寸小、延迟范围大、入射能量和延迟时间连续可调的优点，为上海硬X射线自由电子激光装置的分束延迟系统研制提供参考。

Time resolution in the picosecond to nanosecond range is difficult to achieve for a hard X-ray free-electron laser device. To solve this problem, a split-delay optical system design for a hard X-ray free-electron laser device currently under construction in Shanghai is proposed. The design is based on crystal diffraction, the delay time range is calculated, the system throughput is simulated, and a prototype is built and verified. The design can split a single X-ray pulse into two fractions using the spatial division method, and a time delay is introduced between the fractions by using different path lengths. The prototype can operate over a wide and continuous energy range between 7 and 11 keV and provide a delay from -15.4 to 503.3 ps. Throughputs of 33.54% (upper) and 33.64% (lower) for the split-delay optical system were simulated by Shadow, meeting the objective of a 1∶1 ratio. An alignment experiment for the prototype was conducted with a green laser, and the results demonstrate that the prototype can recombine the two beams after spatial division, laying the groundwork for future X-ray verification experiments. The design has the advantages of a small size, wide delay range, and continuously adjustable incident energy and delay time, which can facilitate the development of a split-delay optical system for the Shanghai hard X-ray free-electron laser device.