Study of CM512 Injection in Subjects With Chronic Spontaneous Urticaria(CSU)

Inclusion Criteria: * Voluntarily sign the Informed Consent Form. * Age ≥ 18 years old and ≤ 75 years old. * Patients with a diagnosis of CSU before screening visit, and the duration was ≥6 months. * Pruritus and wheals existed for more than 6 weeks before screening, despite regular H1-Antihistamines(AH) treatment during this period. * A stable dose of the second-generation H1-Antihistamines(AH) has been continuously used for at least 7 days before randomization, and the individual is willing to continue to use it stably as stipulated in the protocol during the study period. * Within 7 days before randomization, UAS7≥16 and ISS7 ≥8. Exclusion Criteria: * Not enough washing-out period for previous therapy. * Planned major surgical procedure during the patient's participation in this study. * Has ever experienced a systemic allergic reaction or immediate allergic reaction to any biological product (including any excipients). * CM512 has been used before. * Women who are pregnant or breastfeeding. During the study period, subjects who had plans to have children, or did not agree to contraception. * With any medical or non-medical conditions that are not suitable for participation in this study by investigators.