Objective\ To investigate the effect and safety of LMWH on treatment of nephrotic syndrome(NS).Methods\ We randomized 43 patients with primary NS into 2 groups.Steroid and cyclophosphamide were given in control group.LMWH with the dosage of 3200～5000IU twice per day was added in the treated group.Results\ After 4 to 6 weeks of treatment,a significant increase in AT-Ⅲ,anti-Xa activity and serum albumin and decrease in fibrinogen and proteinuria were observed in LMWH.Conclusion\ LMWH should be recommended as a useful treatment of NS.