This study is a multicenter, randomized, open-label, parallel Phase III clinical trial. 650 early-stage or locally advanced breast cancer participants will be enrolled and randomly assigned to SHR-A1811 monotherapy group (trial group) or TCbHP treatment group (control group) at a 1:1 ratio. Participants will receive neoadjuvant treatments of SHR-A1811 or TCbHP, while those who have completed neoadjuvant therapy and are suitable for surgery must undergo surgical treatment. The participants will be evaluated on tumor efficacy through postoperative pathological assessment by IRC and pathologists from the research center. The primary endpoint will be tpCR evaluated by IRC. Participants who complete surgical treatment will be followed up for at least 3 years at study endpoints such as EFS, DFS, and DDFS.

Inclusion Criteria:

1. Females treated for the first time, 18-75 years old;
2. ECOG score 0-1;
3. Has pathological diagnosis that meets the criteria: confirmed HER2 positive;
4. Results of laboratory tests meet the enrollment requirements;
5. Pregnancy test result must be negative and must agree to contraception;
6. Has signed the informed consent form.

Exclusion Criteria:

1. Confirmed HER2 negative;
2. Has tumor-related medical history or treatment history;
3. Has severe combined disease/medical history and treatment history;
4. Has received treatment with systemic immunostimulants or immunosuppressants;
5. Be allergic to the test drug;
6. Participate in other clinical trials simultaneously;
7. Has received vaccine within 30 days before the first dose;
8. Has received allograft bone marrow transplantation;
9. Has given birth within one year or is breastfeeding;
10. Has history of psychological drug abuse, alcoholism or drug use.