Abstract: To impart fluorescent properties to transparent polyimide (PI) films for diverse application needs, incorporating inorganic or organic fillers into the PI matrix to create composite films presents a straightforward and effective modification approach, beyond solely relying on molecular structure design.This paper proposes a method for preparing composite membranes by blending colorless and transparent polyimide (PI) as the matrix with organic fluorescent molecules. Firstly, the green fluorescent compound 2-(benzothiazole)-3-(2-hydroxynaphthyl)acrylonitrile (G) was synthesized. Then, 1,4-bis(4-amino-2-trifluoromethylphenoxy)benzene (6FAPB) was selected to polymerize with 1,2,3,4-cyclobutanetetracarboxylic dianhydride (CBDA) to obtain a poly(amic acid) solution. Different proportions of G were then added, and after thorough mixing, the solution was cast into a film. The PI(6FAPB-CBDA)-G composite membranes were prepared through thermal imidization. As the content of G increased from 0% to 1.2%, the glass transition temperature of the PI(6FAPB-CBDA)-G membrane decreased from 328℃ to 307℃, and the tensile strength decreased from 119.1 MPa to 89.7 MPa. When the content of G was 1.2%, PI(6FAPB-CBDA)-1.2G exhibited the highest fluorescent intensity and excellent stability, with aquantum yield of 40.18%. In addition, all the composite membranes had good transparency and were soluble in polar aprotic solvents. The green fluorescent PI composite material film has excellent comprehensive performance, which can be used in anti-counterfeiting, optoelectronic devices, intelligent response and other fields.