Abstract: In order to probe into the effect of commonly used collectors on low-rank coal flotation performance, an investigation is made of the effect of dosage of diglycolamide laurate (DL) on promotion of flotation of long-flame coal using the long-flame coal from Hongliu Coal Preparation Plant as test sample. Test result shows that the use of diglycolamide laurate may lead to enhanced hydrophobicity of coal particle surface due to absorption of DL onto oxygen-containing functional groups through amide group bonds, and, hence, the increased yield of concentrate and improved flotation perfection index. When DL is prepared with diesel in a ratio of 1∶15, a much better promotion effect can be expected.