The purpose of this study is to evaluate the efficacy and safety of Remimazolam Tosilate for Injection for sedation in the ICU.

Inclusion Criteria:

1. Patients and/or their guardians are able to provide a written informed consent, understand and agree to comply with the study requirements and protocol.
2. Subjects have been treated with endotracheal intubation and mechanical ventilation, and are expected to receive sedation after randomization at least 6 hours. The target sedation level during the period is -2 ≤ RASS ≤ +1.
3. 18 years to 80 years old, male or female.
4. 18 kg/m2 ≤ BMI ≤ 30 kg/m2.

Exclusion Criteria:

1. Deep sedation is required, or continuous sedation is not needed during the study process.
2. Participants (other than in endotracheal intubation) who are expected to require neuro-muscle blockers during sedation.
3. History of epilepsy or status epilepticus.
4. Myasthenia gravis or a history of myasthenia gravis.
5. Severe arrhythmias or heart disease; the circulatory system is unstable.
6. Subjects with a history of severe cardiovascular disease, or cerebrovascular disease, or neurological disease, or mental illness.
7. Subjects with a history of drug abuse.
8. Organ failure before randomization.
9. Abnormal values of the laboratory examination.
10. Allergic to relevant drugs ingredient or component.
11. Pregnant or nursing women.
12. Subjects who has participated in clinical trials of other interventions recently.
13. Other conditions deemed unsuitable to be included.