This is a multicenter, randomized, double-blind, etomidate-controlled phase III clinical trial. The primary objective is to compare the efficacy and safety between ET-26 and etomidate in the induction of general anesthesia in subjects undergoing elective surgery, so as to provide a reference for the marketing registration of methoetomidate hydrochloride for injection.

Inclusion Criteria:

1. Inpatients requiring tracheal intubation under general anesthesia for Non-emergency, non-cardiothoracic, non-extracranial elective surgery estimated operation duration ≥ 0.5h;
2. Age ≥ 18 and ≤ 70 years old, gender is not limited;
3. ASA（American Society of Anesthesiologists） Class I-II;
4. Body mass index (BMI) 18 ~ 30 kg/m2 (including boundary value);
5. Serum cortisol concentration test is normal or abnormal but judged no clinical significance by the investigator;
6. Vital signs during screening: respiratory rate≥ 10 and ≤ 24 breaths /minute; When breathing air, pulse oxygen saturation (SpO2)≥95%; Systolic blood pressure (SBP) ≥ 90mmHg and ≤160mmHg; diastolic blood pressure (DBP) ≥ 60mmHg and ≤100mmHg; heart rate (ECG results) ≥ 55 and ≤ 100 beats/min;
7. Subjects must understand the procedures and methods of this study and be willing to sign informed consent and strictly abide by this trial protocol to complete the study.

Exclusion Criteria:

1. Subjects with contraindications to general anesthesia or previous history of anesthesia accidents, and other systemic medical history that increases the risk of anesthesia;
2. Known or suspected family history of malignant hyperthermia;
3. Known or suspected of being allergic or contraindicated to the procedural medication prescribed in each component or regimen of the experimental drug, suspected of epilepsy or severe liver and kidney dysfunction;
4. Difficulty in intubation or ventilation is expected (Modified Mallampati Score of Ⅲ and Ⅳ);
5. Presence of any of the following respiratory management risks before/at screening: 1) history of asthma, stridor; 2) Patients with sleep apnea syndrome;
6. Any of the following drugs or treatments were used prior to screening: 1) those who participated in any drug clinical trial within 1 month prior to screening; 2) Have used drugs or treatments that affect cortical function within 3 days before screening; 3) Use of drugs that may affect the QT interval within 2 weeks prior to screening;
7. The laboratory examination indicators during the screening period meet the following standards:

1) AST and /or ALT ≥ 3×ULN; 2)TBIL≥1.5×ULN； 3) Hb≤90 g/L (and no blood transfusion within 14 days); 4)ANC≤1.5×109/L； 5)PLT≤80×109/L； 6) Blood Serum creatinine ≥1.5×ULN; 8. Pregnant and lactating women; the reluctance of fertile women or men to use contraception throughout the trial; subjects (including male subjects) who had pregnancy plans within three months of the trial; 9. Subjects who have any other factors deemed unsuitable for participation in this study by the investigator.