TECHNOLOGY FOCUS - INORGANIC CHEMISTRY - Preferred Components: The dehydrogenation agent is lithium hydride or sodium hydride. The alkali solution is sodium hydroxide or potassium hydroxide solution.    TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preferred Components: The solvent is N,N-dimethylacetamide, dimethylsulfoxide, N-methylpyrrolidone, or N,N-dimethylformamide. The quaternary ammonium halide is of Formula H3C-N(CH3)-R2-R3R2=(CH2)x;x=1-10; andR3=chlorine, iodine, or bromine.. The precipitator is acetone, methanol, ethanol, tetrahydrofuran, or ether.    TECHNOLOGY FOCUS - POLYMERS - Preparation: The preparation method of the quaternized polybenzimidazole comprises (1) adding polybenzimidazole into solvent, stirring and adding reflux device, and dissolving for 6-30 hours at 100-250 degrees C, where the mass concentration of polybenzimidazole in the solution is 0.2-5%; (2) adding dehydrogenation agent into the solution prepared in step (1) to carry out dehydrogenation reaction for 4-36 hours, adding quaternary ammonium halide into the product at 70-150 degrees C, reacting for 12-40 hours, adding the prepared product into the precipitator, washing, and drying, where the mole ratio of dehydrogenation agent and polybenzimidazole is 1.5-20 and the mole ratio of quaternary ammonium halide and polybenzimidazole is 2-10; (3) adding the product prepared in step (2) into the solvent, stirring and adding reflux device, dissolving for 6-30 hours at 100-250 degrees C, where the mass concentration of polybenzimidazole in the solution is 0.2-5%; (4) adding methyl iodide into the solution prepared in step (3) to react for 10-30 hours at 35-41 degrees C, adding the prepared product into the precipitator, washing, drying, carrying out ion-exchange in alkali solution, and vacuum drying to prepare the quaternized polybenzimidazole. Preferred Products: The quaternized polybenzimidazole has repetitive structural units of benzimidazole of Formula IIm=10-2000;R1=(CH2)n, benzene derivatives of Formula (1-2), naphthalene derivative of Formula (3), biphenyl derivative of Formula (4), cyclohexyl, pyridine-2,5-diyl, quinolin-2,6-diyl, or trans or cis of CH=CH;n=0-28; andY=O, S, SO2, CO, CH2, C(CH3)2, or C(CF3)2.