A micro spectrum chip based on units of different shapes. The micro spectrum chip includes a CIS wafer and an optical modulation layer. The optical modulation layer includes several micro-nano structure units arranged on the surface of a photosensitive area of the CIS wafer. Each micro-nano structure unit includes a plurality of micro-nano structure arrays, and in each micro-nano structure unit, different micro-nano structure arrays are two-dimensional gratings composed of internal units of different shapes. In each micro-nano structure unit in this scheme, different micro-nano structure arrays have different shapes of internal units, and each group of micro-nano structure arrays have different modulation effects on lights with different wavelengths. The degree of freedom of “shape” is fully utilized to obtain a rich modulation effect on the incident light. A two-dimensional grating structure based on internal units of different shapes is utilized.