Sulf, as the 6-O endosulfatase of heparan sulfate proteoglycans (HSPGs), has been reported in many previous works that it plays the significent role in the pathogenesis of a variety of human cancers. Here we proposed that instead of concentration, the actived Sulf will be more critical in this process. However, there are very few reports about point-of-care method to evaluate sulf 1 activity currently. In this work, an electrochemical method using HSPGs as a substrate was employed to detect the concentration of sulf 1. HSPGs, a glycoprotein with the common characteristic of containing one or more covalently attached heparan sulfate (HS) chains, is a type of glycosaminogly can mediate the activation of a variety of cell growth factor signal pathway to promote the progression of cancers. The disaccharide units of HS chains have four different sulfation modification sites, which are substituted on the N-, 3-O, and 6-O positions of glucosamine and the 2-O position of uronic acid residues. Considering sulf 1 can transform the 6-O sulfation of HSPGs to OH group, as shown in figure 1, the structure and electrical property of HSPGs could take some changes. Here, electrochemical impedance spectroscopy (EIS) was used to detect the changes of electrical property of HSPGs before and after reacting with sulf standard solution. Through analyzing and calculating the electrical parameters obtained by EIS, such as charge, capacity and degree of phase, we established the calibration curve of sulf concentration, which could be further used to detect the sulf concentration of human blood samples. This work offers a new method for sulf detection and has great potential in the early detection of lung cancers.