Abstract: Six novel hydronopyl gemini quaternary ammonium salts containing rigid alkyl chain groups, namely dibenzyl-1, 4-bis(hydronopyl dimethyl ammonium bromide)(3a), dibenzyl-1, 4-bis(hydronopyl diethyl ammonium bromide)(3b), dibenzyl-1, 4-bis(hydronopyl di-n-propyl ammonium bromide)(3c), dibenzyl-1, 4-bis(hydronopyl dimethyl ammonium chloride)(3d), dibenzyl-1, 4-bis(hydronopyl diethyl ammonium chloride)(3e), and dibenzyl-1, 4-bis(hydronopyl di-n-propyl ammonium chloride)(3f) were synthesized from hydronopyl tertiary amine compounds and 1, 4-dibenzyl bromide(chloride), respectively. Their structures were confirmed by FT-IR, MS and NMR. The antifungal activities of the novel compounds against eight plant pathogens were evaluated by mycelium growth rate method. The results showed that six hydronopyl gemini quaternary ammonium salts containing rigid alkyl chain groups had obvious antifungal activities against 8 plant pathogenic fungi. Among them, the EC₅₀ values of all the compounds against Fusicoccum aesculi were lower than 10 mg/L, and the EC₅₀ values against Coriolus versicolor and Fusarium oxysporum were lower than that of chlorothalonil. The antifungal activities of compounds 3a, 3b and 3c against Rhizocyonia solani, Colletotrichum gloeosporioides, Sphaeropsis sapinea and Fusicoccum aesculi showed a rise as the molecular weight of linkers.Compound 3f had good antifungal activity against Colletotrichum gloeosporioides, and the EC₅₀ value was 3.447 8 mg/L.