This study is divided into Stage I and Stage II. It is planned to include 156 subjects who need CRRT treatment for more than 48 hours.

Inclusion Criteria:

1. Male or female aged ≥18 and ≤80;
2. 16 kg/m2 ≤BMI≤35 kg/m2;
3. Those who need CRRT treatment for more than 48 hours and plan to use CVVHDF treatment mode for femoral vein puncture;
4. Subjects or their guardians voluntarily sign the informed consent form in writing before any procedure related to the study starts, fully understand the purpose and significance of this trial, and are willing to comply with the trial protocol.

Exclusion Criteria:

1. Those who are known to be allergic to heparin, heparin drugs, investigational drugs or non-active ingredients of study intervention;
2. Subjects with severe coagulation dysfunction or bleeding tendency three months before the screening, such as HIT (heparin-induced thrombocytopenia), ITP (idiopathic thrombocytopenia purpura), TTP (thrombocytopenia purpura), persistent systolic blood pressure>200 mmHg or diastolic blood pressure>120 mmHg, active gastrointestinal bleeding, intracranial hemorrhage, cerebral aneurysm, severe retinopathy bleeding, hemophilia, hemolytic uremic syndrome, stroke, acute coronary syndrome;
3. Those who have undergone major cardiac surgery or craniocerebral surgery within 3 months before screening and who are judged by the study doctor to be at risk of serious bleeding;
4. Those whose platelet ≤ 50*109/L and/or INR>1.8 and/or aPTT>55s at screening;
5. Those who need to combine other blood purification methods such as blood perfusion or ECMO;
6. The time from the point of randomization to the last use of anticoagulants (low-molecular-weight heparin, warfarin, apixaban, bivalirudin, etc.), antiplatelet drugs (clopidogrel, aspirin, etc.), fibrinolytic drugs (urokinase, etc.) is shorter than the 5 half-lives of the drug or the duration of drug efficacy (calculated by the longest time);
7. The time of administration is shorter than 1 half-life of low-molecular-weight heparin from the last preventive dose;
8. Child-Pugh liver function is grade C in screening period;
9. Those with positive hepatitis C antibody or HIV antibody screening;
10. Pregnant and lactating women; women or men with fertility are unwilling to use contraception throughout the study period; subjects with pregnancy plans within 6 months after the study (including male subjects);
11. Those who have participated in clinical trials of other drugs within 3 months before screening (defined as having received investigational drug or placebo);
12. Other conditions that the investigator judges are not suitable for the subject to participate in the clinical trial.