In this paper, flotation performances of low-rank coal were investigated in the 2-ethyl hexanol, DAH (dodecyl amine hydrochloride), and SDS (sodium dodecyl sulfate) solutions, respectively. In order to reduce the heterogeneity and hydrodynamic effects on the hydrophobicity and movement trajectory of low-rank coal particles, respectively, experimental coal samples with low ash content and 0.500-0.250 mm in size fraction were adopted. XPS result demonstrated that the total silicium and aluminum content of 0.500–0.250 mm size fraction was 1.58%. It was also found that the ash content of 0.500–0.250 mm size fraction was 1.91%. Therefore, it demonstrated that there were few hydrophilic mineral particles on the coal sample surface. Thus, the heterogeneity effect of hydrophilic mineral particles during sliding process measurements can be ignored. XPS result also indicated that after grinding process the mineral content on low-rank coal surface was very small, which would play a small role in the hydrophobicity of low-rank coal samples. The flotation results indicated that the hydrophobicity of low-rank coal particles could be improved by nonionic 2-ethyl hexanol and cation DAH surfactants. Moreover, from the analysis of slip angle velocity, it demonstrated that the flotation responses of low-rank coal were depressed by anionic SDS. Furthermore, it was observed that the slip angle velocity can be used to evaluate the effect of surfactant agents on the flotation performance of low-rank coal while the surfactant concentration was more than 10-6 mol/L.