This is a randomized, double-blind, placebo-controlled, single dose escalation phase 1 study. The objective of this study is to evaluate the safety, tolerability, pharmacokinetics and immunogenicity of subcutaneous administered SHR-1905 in healthy subjects.

The study will consist of one dose esclation part with a total of 5 dose levels. The Subjects will be randomized to receive SHR-1905 as reflected by the guiding principle for the dose esclation/expansion phase. Each dose group includes a screening period, a baseline period, an observational period, and a safety follow-up period.

Inclusion Criteria:

1. Ability to understand the trial procedures and possible adverse events, volunteers to participate in the trial.
2. Male or female aged between 18 years and 55 years (inclusive) at the date of signed consent form.
3. Total body weight ≥45 kg at screening, and body mass index (BMI) between 18 and 28 kg/m2 (inclusive).
4. For healthy subjects, no clinically significant abnormalities.
5. Men and women of childbearing potential (WOCBP) must agree to take effective contraceptive methods

Exclusion Criteria:

1. Known medical history of severe disease in cardiovascular, liver, kidney, digestive tract, mental nerve, hematology, metabolic disorders, etc.
2. Severe injuries or major surgeries within 6 months before screening.
3. Subjects with infecious disease.
4. Hyper/Hypotension at screening and at check in.
5. Clinically significant abnormalities in 12-Lead ECG
6. More than 5 cigarettes daily (or products with equivalent amount of nicotine) for 3 months prior to screening
7. Positive urine drug screen .
8. Subject who cannot perform venous blood sampling.
9. Known history or suspected of being allergic to the study drugs and their excipients.
10. Use of any medicine within 4-weeks or within 5 half-lives
11. History of alcohol abuse within 3 months prior to the IP administration .
12. Participation in clinical trials of other investigational drugs or medical devices within 3 months prior to screening
13. in the investigator's judgment, may increase the risk to the subject