The present invention relates to graphite alkene iron lithium phosphate positive active material, a preparing method thereof, and a lithium ion twice battery based on the graphite alkene modified iron lithium phosphate positive active material. Graphite alkene and iron lithium phosphate are dispersed into water solution to be mixed evenly by stirring and ultra audible sound, then, are dried to obtain iron lithium phosphate material compounded by the graphite alkene and the iron lithium phosphate to be annealed by high temperature, and finally, the graphite alkene modified iron lithium phosphate positive active material is obtained. Compared with traditional carbon coated and conductive polymeric adulteration modified lithium batteries, the lithium ion twice battery based on the graphite alkene modified iron lithium phosphate positive active material has the advantages of high battery capacity, good charging-discharging circulating performance, long life and high circulating stability, and has great utility value.