Abstract: Through measuring the contact angle, Zeta potential and infrared spectrogram of the coal sample in the case of using respectively the high-efficiency M5419, diesel and kerosene as collecting reagent, the abilities of the above cited 3 kinds of collectors for catching coal particles are compared. As evidenced by result of open-circuit test made with the low-sulphur high-ash fine coal of Jinjia Coal Mine, Guizhou Province, using the 3 kinds of collecting agents, compared to the use of the latter 2 collectors, the use of M5419 can lead to a rise of concentrate yield by 6.54% and 6.79% respectively, an increase of combustible matter recovery rate by 7.83% and 5.66%, an increase of contact angle of coal sample by 3.5° and 2.4°, and an increase of difference in isoelectric point by 3.24 and 1.91. Closed-circuit test run encompassing "one-stage roughing, 3-stage scavenging and 4-stage cleaner operations" is also made with M5419 as collecting agent. Test result shows that with the use of M5419, the coal slime can be effectively separated as evidenced by the drop of concentrate ash down to 5.64%, a rise of the recovery rate of combustible matter up to 88.70% and a recovery rate of fixed carbon reaching as high as 99.03%.