The invention relates to a formula of a blood filtration replacement fluid which is special for citrate anticoagulation, a preparation method and a usage thereof. With the components of sodium citrate, sodium chloride, potassium chloride, sodium lactate, citric acid and so on, the replacement fluid is mainly used for blood filtration and blood dialysis filtration of the patients with acute renal failure or high risk bleeding due to multiple organ failure etc., and can solve the problems of easy occurrence of hypernatremia and alkali poisoning in the prior citrate anticoagulation, thus facilitating the clinical usage. The replacement fluid has the advantages of strong applicability, exact efficacy and low toxicity and side effects; the preparation process is simple; the quality is stable, safe and effective; the feasibility is strong; the repeatability is high; and the replacement fluid is applicable to the large-scale production and the promotion of the clinical application, thus being the ideal blood filtration replacement fluid for blood filtration, blood dialysis filtration, continuous renal replacement therapy and so on. The demand of the blood dialysis increases along with the increasing number of the patients with the end-stage renal failure year by year, so the blood filtration replacement fluid can generate more tremendous economic and social benefits.