The invention relates to a lens refractive index measuring device and method, the device comprises a diopter measuring module, an optical thickness measuring module, a confocal reflection measuring module and a measured lens, the diopter measuring module comprises a first light source module, a first collimating lens, a Hartmann diaphragm and a photoelectric detector Cam; the optical thickness measurement module comprises a second light source module, a second collimating lens, a third light source module, a third collimating lens, a focusing lens, a first beam splitter, a second beam splitter, a third beam splitter, a fourth beam splitter, a reflector, a photoelectric detector D1 and a photoelectric detector D2. The confocal reflection measurement module comprises a luminous source, a photoelectric detector D3, a Y-shaped optical fiber, a lens group and a mesoporous prism, the Y-shaped optical fiber comprises a first port, a second port and a third port, the device reduces the number of optical elements, simplifies the optical structure, is convenient to operate, reduces the cost, and reduces the space occupied area of the device.