ObjectiveTo study the relationship between preoperative pan-immune-inflammation value (PIV), preoperative hemoglobin, albumin, lymphocyte and platelet score (HALP) and tumor pathological features and microsatellite status of colorectal cancer, and to analyze the predictive value of HALP and PIV for microsatellite status. MethodsThe clinicopathological data of 156 patients who underwent radical colorectal cancer resection admitted to the Second Hospital of Shanxi Medical University from May 2021 to February 2024 were retrospectively analyzed. HALP and PIV were calculated by preoperative related laboratory indicators, and then the patients were divided into high HALP/low HALP (HHALP/LHALP) group (n=78) and high PIV/low PIV (HPIV/LPIV) group (n=78) according to the median of their calculated values. The correlation between preoperative HALP and PIV and clinicopathologic features of colorectal cancer was analyzed. According to the results of microsatellite stability detection, the patients were divided into microsatellite standard/microsatellite instability-high（MSS/MSI-H）group. The correlation between preoperative HALP and PIV and microsatellite stability was analyzed. The predictive value of HALP and PIV for microsatellite status was analyzed by using receiver operating characteristic (ROC) curve. ResultsThere were statistically significant differences in tumor diameter, tumor location, HALP, T stage and microsatellite status between the HPIV group and the LPIV group (P<0.05), and high PIV was more common in patients with right-sided colon cancer and MSI-H, and the tumors were larger and had higher T stage. The differences in gender, body mass index（BMI）, tumor diameter, tumor location, PIV, T stage and microsatellite status between the HHALP group and the LHALP group were statistically significant (P<0.05), and low HALP was more common in women, patients with right-sided colon cancer, and MSI-H, and had a low BMI, large tumors, and high T stage. There were statistically significant differences in HALP and PIV between MSS group and MSI-H group (P<0.05), and patients with MSI-H tended to have low HALP and high PIV, and the area under curve of HALP and PIV in predicting MSI-H for colorectal cancer was 0.848 9 and 0.851 6, respectively, and the optimal cut-off value was 26.84 scores and 507.04, respectively, and the sensitivity was 1.000, 0.923, specificity 0.643, 0.817, respectively. ConclusionLow HALP and high PIV are more common in patients with right-sided colon cancer and MSI-H, who have poor nutritional and immune status, severe inflammation, larger tumors, deeper invasion, and predictive value for MSI-H, which can assist in the formulation of clinical treatment plans to a certain extent.