This work develops a method for constructing nearly flat bands with arbitrary Chern number $C$ in momentum space and further reconstructing their corresponding real-space models. In the two-band case, starting from a known topological flat band with $C=1$, we systematically generate nearly flat bands with $C=n$ through the repeated application of unitary transformations to the initial Hamiltonian. The approach is successfully applied to the Haldane model and the checkerboard model. In the three-band case, we select the simplest form of Hamiltonian and introduce unitary transformations coupled with band inversion to achieve nearly flat bands with high Chern numbers. Furthermore, for a specific type of kagome model, we separate its Hamiltonian into real and imaginary parts, and construct its coefficient vector in analogy to the two-band case, thereby also obtaining high Chern number nearly flat bands.

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• Electronic structure
• Flat bands
• Topological phases of matter