Abstract: HLB values of eight heavy oil samples of Shengli oilfield were measured by conventional method, and the correlations between the HLB value and the inverted point and the hydroxyl absorption area were studied. The results show that HLB value, inverted point and hydroxyl absorption area of the 8 samples have the same order: xin6xie6>kendong52pai222>shengtuo3pai12xie181>kendong52pai225>xin68xie87>shan56pai11geng9>shan56pai4xie4>caoku126. The reason from the perspective of oil-water interface layer is that the oil-water interface layer is made up of asphaltene aggregates and their chains as well as polar functional groups. The higher HLB values of the oil, the stronger the interacting forces and the emulsifying ability, resulting in higher moisture inverted point and more the functional groups. The quantitative relation shows that for the five ordinary heavy oils, the ratio of the inverted point to the HLB value is 6 and the ratio of the HLB value over the absorption peak area of hydroxyl respectively is 0.1. While for the three super heavy oils, the above two ratios are 5, and 0.015, respectively. It is concluded that using the HLB value to measure heavy oil emulsifying ability is reasonable.