In this investigation, the flotation behavior of oxidized coal affected by the conditioning time separated into two periods: prewetting time and collector conditioning time, were discussed. The prewetting time is 0 min, 1 min, 2 min, 3 min, 4 min, and 5 min, respectively. The collector conditioning time is 1 min, 2 min, 3 min, 4 min, 5 min, and 6 min, respectively. Fourier-transform infrared was used to analyze the chemical property of oxidized coal and fresh coal. The results show that the oxidized coal surface is more hydrophilic than the fresh coal. The results of flotation tests show that combustible matter recovery will be higher while the prewetting time is shorter. The mechanism of effects of conditioning time on the flotation of oxidized coal was discussed.