NOVELTY - A multiphase ion-electron mixed conductor powder material, is new.    USE - The multiphase ion-electron mixed conductor powder material is useful as membrane material that selectively separates out oxygen from oxygen mixed gas, and as electrode material of solid oxide fuel battery and oxygen sensor.    ADVANTAGE - The multiphase ion-electron mixed conductor powder material obtained by method of adulteration and modification is provided with fine structural stability under inert atmosphere and strong reducing atmosphere, and is provided with excellent oxygen permeability in partial oxidation experiment of the COG (coke oven gas) methane, simultaneously provided with high-stable oxygen ion conduction and electron conduction proprieties; it is a mixed conductive material. Thus, it can be used as membrane material that selectively separates out oxygen from oxygen mixed gas, and as electrode material of solid oxide fuel battery and oxygen sensor. It is applied in membrane reactor so that the reaction is high-temperature oxidation reaction, such as, the partial oxidation of methane to synthesize gas, oxidative coupling reaction dynamically-provided oxygen, simplifying the operation process and decreasing the operation expenditure.    DETAILED DESCRIPTION - The multiphase ion-electron mixed conductor powder material, is new. The first phase of the conductor material is Barium (Ba)Cobalt (Co)xIron (Fe)yNiobium (Nb)zO3-delta.    BCFN, x, y, z = is mol fraction; where x is more than or equal to 0 but less than or equal to 0.9; y is more than or equal to 0 but less than or equal to 0.6; z is more than or equal to 0 but less than or equal to 0.3; x+y+z is more than or equal to 0.95 but less than or equal to 1.1.    The second phase of the conductor material is Zirconium oxide (ZrO2), aluminum oxide (Al2O3) or Tin oxide (SnO2); where the mol fraction of adulterant relative to BCFN is not more than 20%. INDEPENDENT CLAIMS are:    (1) a method of preparing multiphase ion-electron mixed conductor powder material comprises: (1) preparing BaCoxFeyNbzO3-delta powder; weighing each needed raw material according to chemical measurement of the BCFN; where the raw materials are oxide, carbonate, oxalate or nitrate of metal Ba, Co, Fe and Nb; using ethanol or water as dispersant to carry out ball milling and combine the raw materials; combining evenly and drying, then calcining at a temperature of 1000-1150 centigrade for 10-20 hours; then drying by ball milling to obtain BDFN powder; and (2) sieving the BDFN powder obtained in step a and adulterant ZrO2, Al2O3 or SnO2 in dried powder according to the proportions, combining, or ball milling to combine for 1-2 hours to obtain multiphase mixed conductor powder material;    (2) a multiphase ion-electron mixed conductor membrane, prepared by using the multiphase ion-electron mixed conductor powder material as raw material, and sintering; where the sintering process comprises pressing the multiphase ion-electron mixed conductor powder material into biscuit; warming into 1100-1175 centigrade in a warming speed of 2-5 centigrade per minute, then sintering for 5-20 hours; where preserving heat is for 2 hours at 400 and 900 centigrade; and    (3) a multiphase ion-electron mixed conductor membrane pipe, prepared by using the multiphase ion-electron mixed conductor powder material as raw material, which comprises: (1) adding wax, oleic acid into the multiphase ion-electron mixed conductor powder material; stirring evenly at a temperature of 80-100 centigrade; then vacuum filtering to obtain slurry; rush-casting the slurry into the die cavity to obtain pipe-shaped biscuit; where the adding quantity of wax is 10%-13% of the weight of multiphase ion-electron mixed conductor powder material; the adding quantity of oleic acid is 0.5%~1% of multiphase mixed conductor material; (2) using alumina or magnesite that is pre-burned at a high temperature as absorbing powder; warming the pipe-shaped biscuit into 300 centigrade at a warming speed of 10 centigrade per minutes; preserving heat for 4 hours; then warming into 300-500 centigrade at a warming speed of 15 centigrade per minutes; then warming into 500-900 centigrade at a warming speed of 60 centigrade per minutes; and (3) the secondary sintering process of pipe-shaped biscuit obtained in step (2) which is specifically warming into 1000-1175 centigrade in a speed of 1-5 centigrade per minute, preserving heat for 5-20 hours.