Abstract: Reflectance spectra of ground objects are the foundation of ground remote sensing. In order to detect reflectance spectra of ground objects from various angles, the existing measuring devices are mostly based on complex mechanical transmission platforms and control systems. However, these devices are bulky, costly, and lack of portability. To solve above problems, a reflectance spectra measuring system under detection geometry is designed in this paper. This system consists of four parts: detection geometry bracket, spectra acquisition system, halogen tungsten spotlight, and object stage. Wide range of detection geometry of angle and distance can be achieved by flexible assembling and positioning of main component modules in the detection geometry bracket which adopted modular design; and wide spectral band coverage can be achieved by a one-to-multiple optical fiber adopted by the spectra acquisition system. After trial production and debugging of the system, detection geometry and band range of the system is verified through experiments of reflectance spectra acquisition and test of ground objects. The reflectance spectra measuring system is simple in structure, good in interchangeability, easy to install and carry, and can meet indoor and outdoor needs with strong practicability.