In order to enhance the separation floatation of apatite ore, one mineral oil (MO), a petroleum base oil, as a raw material was modified to obtain a novel high-efficiency collector. The optimized modified mineral oil collector (MPBO) was obtained by systematically modified experiments. The results showed that the optimized condition of modification was air-flow rate 0.15 m3/h, potassium permanganate 0.2% (0.04 g), the reaction time 24 h and the temperature 140 °C. The flotation performance and mechanism of MPBO were further studied by flotation tests, zeta potential measurements, Fourier-transform infrared spectroscopy (FTIR), and X-ray photoelectron spectroscopy (XPS). The results of flotation tests showed that MPBO had a higher selectivity than oxidized paraffin soap. When 400 g/t MPBO was used as collector, the concentrate with 96.89% P2O5 recovery and 26.08% P2O5 grade was obtained. It also indicated that MPBO as the collector not only significantly improved the separation index of apatite ore flotation, but also greatly shortened and simplified the flotation process. The analysis of zeta potential, FTIR spectra and XPS revealed that carboxyl group was presented in the MPBO, which could form calcium carboxylate with calcium ion on the apatite surface by chemisorption.