Objective The aim of this investigation is to determine the potential protective effect and mechanism of a novel non-anticoagulant heparin-derived product on lead (Pb) mediated endothelial cells (ECs) toxicity. Pb is known to have detrimental effects on human health by affecting the function of all systems of the human body due to its toxicity on ECs. Altered activities of the protective substances secreted by the vascular endothelium such as EC's tissue factor pathway inhibiter (TFPI), nitric oxide and other protective factors might increase the risk for vascular disorders. Heparin and its sulfated non-anticoagulant low molecular weight heparin (S-NACH) are known to enhance TFPI release from ECs, which is a protective mechanism for the ECs against thrombo-inflammation. Methods We examined 3-100 mu M Pb-induced dysfunction on ECs and the potential protective effect of 1-10 mu M S-NACH in returning the ECs' normal function. Methods included an in vitro tube formation assay and an in vivo Matrigel plug angiogenesis model in mice. Results We found that Pb-induced EC dysfunction by inhibiting EC viability. The cytotoxic effect of 3-100 mu M Pb on ECs inhibited angiogenesis in a dose-dependent manner. Pb disrupted ECs' normal physiological function by hindering the release of its endogenous vascular protective mediators TFPI-1 and TFPI-2. The impairment effect of 3-30 mu M Pb on ECs' release of both TFPIs was effectively reversed to normal levels by S-NACH in a concentration-dependent manner and combatted the harmful Pb effects on physiological angiogenesis. Conclusions Our data indicate that S-NACH, which is devoid of bleeding side effects, can effectively reverse potentially high-risk Pb-mediated endothelial cytotoxicity by reversing the physiological release of endogenous EC TFPIs.