Based on the concept of quality by design, using the commercially available formulation Linzess^® as the reference preparation, Box-Behnken design-response surface methodology was used to optimize the formulation of linaclotide capsules with the dissolution rate at 10 min as the evaluation index. The optimized formulation was as follows: selecting microcrystalline cellulose pellet core CP-305(with a particle size of approximately 400 μm), the amount of adhesive HPMC at 0.8% (0.96 mg per capsule), and the ratio of calcium chloride to leucine of 3:1 (respectively 1.8 mg and 0.6 mg per capsule). Three batches of self-made preparations were prepared according to above final formulation for validation. The results showed that the content and content uniformity met the requirements. In various pH media, the dissolution rate of three batches of self-made capsules exceeded 85% at 10 min, demonstrating consistent quality with the reference preparation.