The invention discloses a pure-mechanical and chemical-free large-scale chip thinning method based on nanometer diamond particles and belongs to the technical field of flexible ductile photonic/electronic devices, semiconductors and micro-electronics. With the method, the nanometer diamond particles are used as grinding materials for performing pure-mechanical and chemical-free thinning on various chip materials (such as electronic and photonic chips and the like); in the thinning process, roughness, moderateness, fine grinding and polishing are regulated and controlled by changing the particle size of nanometer diamond; and large-scale thinning of the chips of different sizes is realized through regulation and control on the size of chip grooves of chip trays. The method is applicable to large-scale thinning of various chip materials and is applicable to thinning to any thickness, the final thickness can reach about 10 [mu]m, and the required device thickness of the flexible ductile photonic/electronic devices can be well fit.