An organic soluble and high molecular weight pulyetherimide(HQDPA-DMMDA) was synthesized based on the HQDPA and DMMDA in NMP by the low temperature solution co-polymerization method．The structure and properties of the PI were characterized by measurements of FT-IR

WAXD

TGA and DSC etc．The results showed that the obtained polyetherimide had an amorphous structure with a d-spacing of 0.5163 nm．The PI was readily soluble in polar solvents such as NMP

DMF and THF etc．Its glass transition temperature was 251℃ and 10％ thermal decomposition temperature under N2 was 528℃．The tensile strength was 107 MPa and the elongation at break was 24％．The permeability data of polyimide membrane for gases such as H2

N2

O2

CO2 and CH4

were collected at 25℃．The permeability for H2 was 3.809 Barrer and the ideal selectivity coefficients for H2／N2 and H2/CH4 were l66.9 and 214.0

respectively．The permeability for N2

O2

CO2 and CH4 were between 0.018～0.576 Barrer.