背向散射光诊断系统是惯性约束聚变实验中的重要诊断装置。概述了神光Ⅲ原型激光装置背反系统的基本结构和工作原理，详细介绍了一种全口径光斑透过率和光谱响应标定方法。该方法以高功率激光光源和氙灯光源作为标定源，利用特殊的标定光路形成大光斑覆盖背反系统光学元件的全部口径，模拟散射光在全孔径背反系统上的分布，分别对系统的透过率和光谱响应进行了标定。标定结果表明，全孔径背向散射系统受激拉曼散射支路能对波长大于400 nm的光进行传递，在527 nm处的透过率较低。

The backscattered light diagnostic system is an important measurement tool for the ICF experiments. The basic configuration and the optical path of the backscattered light diagnostic system implemented on Shenguang Ⅲ prototype facility are summarized in the paper. Aiming at improving veracity and simplifying the calibration process, a novel full aperture light beam calibration method of transmission and spectrum response is described in the paper. High power laser and white Xe lamp are chosen as calibration resource and a peculiar optical path is erected for modulating the light beam into a full aperture distribution so that the distributing of the backscattered light on the diagnostic system are simulated. Using the method, the transmission and spectrum response are calibrated and several data are shown in the paper. The calibration results show that the SRS branch has a limited wavelength of 400 nm while the path has a poor transmittance at 527 nm.