Aim To explore the effect of lipid metabolism after fat loading on the serum concentration of nitric oxide(NO) and plasm endothelin 1(ET 1) level. Methods 20 healthy subjects were given fat loading after fast for 12～14 h. Peripheral blood examples were drawn before and 2, 4, 6, 8 h after fat loading to determinate the concentration of triglyceride(TG), total cholesterol(TC), low density lipoprotein cholesterol (LDLC), high density lipoprotein cholesterol (HDLC), apolipoprotein A_Ⅰ(ApoA_Ⅰ), apolipoprotein B(ApoB) and glucose(Glu). Concentration of NO and ET 1 at different time point above were detected through colorimetry and radio immune assay respectively. The ratio of NO/ET 1 was calculated. Results TG concentration began to ascent at 2 h(2.19±0.16 vs 1.16±0.11 mmol/L,P<0.05) and reach the peak at 4 h(3.34±0.37 vs 1.16±0.11 mmol/L,P<0.01) after fat loading. During the course, serum level of NO was highest(61.58±5.97 vs 42.50±7.42 ng/L,P<0.05)and ET 1 plasma level was lowest at 2 h (99.08±16.55 vs 114.22±16.45 ng/L,P<0.05). 4 h later, with the descendent of TG concentration, NO and ET 1 concentration came back to the basic level. There was a peak of NO/ET 1 ratio at the 2 h. Conclusions Transient triglyceridemia affects the production of NO and ET 1, which leads to a compensatory increasing production of NO and momently descendent of ET 1 level.