This study aims to evaluate the safety, tolerability, pharmacokinetics and pharmacodynamics of multiple ascending doses of IBI355 in Healthy volunteers. This study also aims to evaluate the anti-Drug antibody after multiple ascending doses of IBI355 in Healthy volunteers.

Inclusion Criteria:

1. Understanding and Signing a written informed consent prior to selection;
2. Aged above 18 years old, male or female;
3. Body mass index (BMI) between 18-28kg/m2;
4. Normal label test;
5. No parenting plan for at least 6 months

Exclusion Criteria:

1. Subjects with a history of allergy；
2. Subjects participated in the other clinical trail in 1 month or less than 5 t1/2 since the previous clinical trial (which is longer)；
3. Subjects with an infection requiring systemic medication was present within 30 days prior to randomization;
4. HIV-Ab、RPR、HCV-Ab、HBV、HBeAg or HBcAb, one of them positive;
5. There have a clinical or imaging evidence that the subject with active tuberculosis, or there is evidence that the subject is in the incubation period for tuberculosis;
6. Patients with a history of central nervous system, cardiovascular system, digestive system, respiratory system, urinary system, blood system, metabolic disorders and other systemic diseases;
7. Subject with a hcg positive;
8. Patients with a history of neuropsychiatry or who are considered unfit to participate in this clinical trial