Objective To compare capillary blood glucose from the 1st and 2nd drop of blood drawn from the finger with venous blood glucose, and to provide reference for capillary blood glucose measurement in clinical settings. Methods The fasting blood glucose concetrations of 210 hospitalized patients were measured and compared in the following way: the patients had a finger puncture and the 1st and 2nd drop of blood were harvested seperately to obtain capillary blood glucose concetrations, which were later compared with venous blood glucose respectively. Results The results of stratified statistical analysis on blood glucose showed that:venous blood glucose values between 2.2-7.0 mmol/L were significantly lower than capillary blood glucose from either the 1st or 2nd drop of blood （P<0.05，P<0.01）; venous blood glucose values >7.0 mmol/L had no significant differences with either type of capillary blood glucose （P>0.05 for all）; overall capillary blood glucose from the 2nd drop of blood had significant differences with venous blood glucose (P<0.01）. Bland-Altman analysis showed that there were significant correlations between each pair of blood glucose types (1st drop vs. venous, 2nd drop vs. venous, 1st drop vs. 2nd drop,P<0.01 for all);there was higher consistency between 1st drop vs. venous blood glucose. Conclusion In the case of using portable glucose meter to monitor blood sugar, capillary blood glucose from the 1st drop of blood, if appropriately harvested, can represent blood glucose levels. Attention should be noted that in the context of the blood sugar greater than 7.0 mmol/L, capillary blood glucose from either the 1st or 2nd drop of blood can represent instant venous blood glucose values.