The purpose of this observer-blind study is to evaluate the safety, reactogenicity and immunogenicity of Meninggococcal (A,C,Y and W135) Conjugate Vaccine in 2 months to 6 years-old children.

Inclusion Criteria:

• Subjects who the investigator believes will comply with the requirements of the protocol should be enrolled in the study.
• Healthy permanent residence 2 months to 6 years old.
• Subjects and parent/guardian able to attend all scheduled visits and comply with all study procedures.
• Axillary temperature ≤37.0 ℃.

Exclusion Criteria:

• History of meningitis infection or vaccination of meningococcal vaccine within the past 6 months.
• Allergic history or any SAE after vaccination, such as allergy, urticaria, dyspnea, angioedema, celialgia.
• Patients administered with immunosuppressive agents, cytotoxicity factor or corticosteroids in the 6 months preceding the vaccine trial.
• Receipt of blood or blood-derived products in the 3 months preceding vaccination
• Participation in another clinical study investigating a vaccine, drug in the 30 days preceding vaccination.
• Receipt of any live virus vaccine in the 15 days preceding vaccination.
• Receipt of any subunit vaccine and inactivated vaccine in the 7 days before vaccination.
• Febrile illness (temperature ≥ 38°C) in the 3 days or any acute illness/infection in the 7 days preceding vaccination.
• Thrombocytopenia.
• History of thyroid gland excision or treatment for thyroid gland disease in last 12 months.
• Functional or anatomic asplenia.
• History of eclampsia, epilepsy, encephalopathy and mental disease or family disease.
• Chronic disease (such as Down syndrome, diabetes, sickle cell anemia or neurologic disease, Guillain-Barre Syndrome).
• Known or suspected diseases, including: respiratory system disease, acute infection or active stage of chronic disease, HIV infection of children or mothers, cardiovascular disease, acute hypertension, cancer treatment, skin disease, etc.
• Any condition that, in the judgment of investigator, may affect trial assessment.