Objective: To investigate the correlation between kaiser score and pathological Miller-Payne grading before and after neoadjuvant chemotherapy for breast cancer. Methods: Eighty-four breast cancer patients admitted to our hospital from January 2019 to December 2021 were selected, and all patients underwent Kaiser score and recorded the score value before receiving neoadjuvant chemotherapy, analyzed the pathological Miller-Payne grading of patients after neoadjuvant chemotherapy and related influencing factors, and calculated the correlation between Kaiser score and Miller-Payne grading after neoadjuvant chemotherapy for breast cancer. Results: Patients received neoadjuvant chemotherapy before Kaiser score value (6.80 ± 1.12), after receiving neoadjuvant chemotherapy Kaiser score value (5.96 ± 1.04), Kaiser score value before chemotherapy than after chemotherapy (P < 0.05); 17 patients achieved complete remission (PCR/G5) after neoadjuvant chemotherapy, did not achieve complete remission (NPCR/G1- 4) patients, 67 patients with NPCR/G1-4 and PCR/G5 patients had statistically significant differences in the percentage of HER-2 positivity and Kaiser score (P < 0.05); univariate and multifactorial analyses showed that HER-2 positive expression and Kaiser score ≤4 were predictors of MP grading, and the differences were statistically significant (P < 0.05). There was a positive correlation between Kaiser score and MP grading, and the difference was statistically significant (r=7.893, P<0.05). Conclusion: Patients receiving preoperative neoadjuvant chemotherapy effectively reduced the Kaiser score, and the Kaiser score was a predictor of achieving complete remission with neoadjuvant chemotherapy in breast cancer patients and was positively correlated with the Miller-Payne grading of patients after chemotherapy.