Abstract: An insulin aspart derivative and a preparation method therefor are provided. The derivative has a fusion protein of a green fluorescent protein folding unit and an insulin aspart precursor or an active fragment thereof. The expression level of the fusion protein is significantly increased, and the insulin aspart precursor protein in the fusion protein is folded correctly and has a biological activity. In addition, the green fluorescent protein folding unit in the fusion protein can be digested into small fragments by a protease, which has a large molecular weight difference compared to the target protein and is thus easy to separate. Further provided is a method for preparing the insulin aspart and an intermediate by means of using the fusion protein.