NOVELTY - Fiber reinforced multi-layer fluorine-containing cross-linked ion membrane comprises 2-40 layers of fluorine-containing ion exchange resin having equivalent value of 600-1300; and layer(s) of single-layer membrane having a cross-linked net structure with total thickness of 10-300 mu m, conductivity of 40-150 ms/cm, and tensile strength of 10-60 MPa. The fluorine-containing ion exchange resin is formed by copolymerizing fluorine-containing alkene, fluorine-containing olefin monomer(s) including functional groups and/or fluorine-containing olefin monomer(s) including cross-linked site.    USE - Fiber reinforced multi-layer fluorine-containing cross-linking ion membrane for use as single-layer membrane of a substrate (claimed).    ADVANTAGE - The resulting ion exchange membrane has high size stability and good mechanical intensity.    DETAILED DESCRIPTION - Fiber reinforced multi-layer fluorine-containing cross-linked ion membrane comprises 2-40 layers of fluorine-containing ion exchange resin having equivalent value of 600-1300. Layer(s) of single-layer membrane is added as reinforce fiber. It has a cross-linked net structure with a total thickness of 10-300 mu m, conductivity of 40-150 ms/cm, and tensile strength of 10-60 MPa. The fluorine-containing ion exchange resin is formed by copolymerizing fluorine-containing alkene, fluorine-containing olefin monomer(s) including functional groups and/or fluorine-containing olefin monomer(s) including cross-linking site. The fluorine-containing alkene is trifluoroethene, hexafluoropropylene, fluoroethylene, or preferably tetrafluoroethylene or trifluorochloroethylene. The fluorine-containing olefin monomer including functional group is of formula Y1(CF2)a(CFRf1)b(CFRf2)cO(C(CF2X)FCF2O)n"-CF=CF2, Rf3CF=CF(CF2)dY2, or F2C=CFOCF2C(CF2OCF3)FOCF2CF2Y3. The fluorine-containing olefin monomer including cross-linking site is of formula F2C=CFRf4Y4, or Y5(CF2)a'(CFRf5)b'(CFRf6)c'O(C(CF2X1)FCF2O)n'-CF=CF2. The cross-linked net structure is of formulae (I)-(V).    a-c=0-1;    d=0-5;    n"=0 or 1;    Rf1-Rf3=perfluoroalkyl or fluorochloroalkyl;    X=F, Cl, Br or I;    Y1-Y3=SO2M, COOR3 or PO(OR4)(OR5);    M=F, Cl, OR', or NR1R2;    R'=Me, Et or propyl, H, Na, Li, K or ammonium radical;    R1, R2=H, Me, Et or propyl;    R3=R1, Na, Li, K, or ammonium radical;    R4, R5=R3;    Y4, Y5=Cl, Br, I or CN;    a'-c'=0 or 1;    X1=F, Cl, Br or I;    n'=0 or 1;    Rf4-Rf6=perfluoroalkyl;    G1=CF2, or O;    G2=CF2 or O;    Rf=2-60C perfluoro carbon chain or fluorine-containing perfluoro carbon chain;    R=methylene or perfluoromethylene;and    n=0-10.    An INDEPENDENT CLAIM is included for a method for preparing the fiber reinforced multi-layer fluorine-containing cross-linked ion membrane comprising preparing each single-layer membrane using molding of solution or liquid melt, extrusion, hot pressing, spin coating, casting, silk net printing, spray painting or soaking. The multi-layer membrane is prepared by the composite between the single-layer membrane. The composition between the multi-layer membrane and the single-layer membrane or the composite between the multi-layer membrane and the multi-layer membrane may be prepared using the molding of solution or liquid melt, extrusion, hot pressing, spin coating, casting, silk net printing, spray painting or soaking on the prepared single-layer membrane. The prepared single-layer membrane can be changed to acid type and then compounded to other obtained membranes, or vice versa.