Inclusion Criteria:  Aged 3-17 years old (all inclusive); The subject voluntarily agrees to participate in the study (or the legal guardian of the subject voluntarily agrees the child to participate in the study), and the guardian and the subject (8-17 years old) sign the informed consent form, and can provide valid identification; Understand and comply with test protocol requirements; The subject and / or the legal guardian of the subject have the ability to understand the (non illiterate) study procedure and participate in the planned follow-up; Axillary temperature < 37.3 ℃ (> 14 years old), axillary temperature < 37.5 ℃(≤14 years old); Female and male subjects of childbearing age agreed to take effective contraceptive measures during the study.  Exclusion Criteria:  The results of physical examination and laboratory examination before screening were abnormal and clinically significant; Any component of the test vaccine, including aluminum preparation, has a history of severe allergy, such as anaphylactic shock, allergic laryngeal edema, allergic purpura, thrombocytopenic purpura, local allergic necrosis reaction (Arthus reaction), dyspnea, angioneurotic edema, etc; Or the above-mentioned serious adverse reactions occurred after the use of any vaccine or drug in the past;  Patients with history of SARS and SARS-CoV-2 (meet any of the following items):  ① History of infection or history of SARS and SARS-CoV-2;  ② During the epidemic of sras-cov-2, there was a history of contact with patients diagnosed / suspected with new crown;  ③ The detection of SARS-CoV-2 IgM and / or IgG antibody was positive;  ④ RT-PCR was positive.  They had taken antipyretics or analgesics within 24 hours before the first dose of vaccine; those who have been vaccinated with New Coronavirus or inoculated with live attenuated vaccine within 30 days within 14 days before the first dose of the vaccine are inoculated with the subunit vaccine and / or inactivated vaccine;  Patients with the following diseases:  ① Patients with acute (within 72 hours) febrile diseases (> 14 years old, axillary temperature ≥ 37.3 ℃; ≤4 years old,axillary temperature ≥37.5 ℃);  ② Digestive system diseases (such as diarrhea, abdominal pain, vomiting, etc.) in the past 7 days;  ③ Suffering from congenital malformations or developmental disorders, genetic defects, severe malnutrition, etc;  ④ A history of congenital or acquired immunodeficiency or autoimmune disease or immunomodulatory therapy within 6 months, such as immunosuppressive dose of glucocorticoid (dose reference: equivalent to prednisone 20mg / day, more than one week); or monoclonal antibody; or thymosin; or interferon, etc; however, local medication (such as ointment, eye drops, inhaler or nasal spray) is allowed;  ⑤ Known to be diagnosed with infectious diseases, such as active tuberculosis, viral hepatitis, present or / or human immunodeficiency virus HIV antibody positive or syphilis specific antibody positive, or parents who are HIV infected;  ⑥ Neurological diseases or neurodevelopmental disorders (e.g., migraine, epilepsy, stroke, seizures in the last three years, encephalopathy, focal neurological deficit, Guillain Barre syndrome, encephalomyelitis or transverse myelitis); History of mental illness or family history;  ⑦ Functional asplenia and splenectomy for any reason;  ⑧ There are serious chronic diseases or disease in progress can not be controlled smoothly, such as diabetes, thyroid disease;  ⑨ Severe liver and kidney diseases; Current respiratory diseases requiring daily medication (e.g., chronic obstructive pulmonary disease [COPD], asthma) or any treatment for exacerbation of respiratory diseases (e.g., asthma exacerbation) in the last five years; A history of severe cardiovascular disease (such as congestive heart failure, cardiomyopathy, ischemic heart disease, arrhythmia, conduction block,myocardial infarction, pulmonary heart disease), or myocarditis or pericarditis;  ⑩ Thrombocytopenia, any coagulation dysfunction or anticoagulant therapy, etc;  ⑪ Cancer patients.  Received blood or blood related products, including immunoglobulin, within 3 months; or planned use during the study period; Have been pregnant (including positive urine pregnancy test), or in lactation; Use any research or unregistered product (drug, vaccine, biological product or device) other than the research product within 3 months, or plan to use it during the research period; Researchers believe that any disease or condition of the subject may put the subject at an unacceptable risk; The subjects could not meet the requirements of the protocol; Interference with the assessment of vaccine response.