This study found that intranasal insulin significantly reduced the risk of POCD and decreased the serum IL-6, TNF-α and S100β in older patients compared to patients treated with intranasal normal saline after laparoscopic radical resection of colorectal cancer, which provides a basis and support for preoperative intranasal insulin in older patients to improve cognitive function and decrease the risk of POCD. This evidence concerns the gene INS and colorectal cancer.