Abstract: ‘Spring Jadeite’ summer squash（Cucurbita pepo L.） seeds were used as experimental materials,the seeds were soaked with CaCl₂ solution, CaCl₂ + Urea disuccinate tetrasodium（HIDS） solution, CaCl₂ + Fulvic acid solution（FA） solution and deionized water（CK） to study the effects of different CaCl₂ reagent combination on seed germination at low temperature,in order to provide reference for improving the cold resistance of summer squash.The results showed that compared with the control,the three treatments with CaCl₂ could improve the germination ability of summer squash seeds under low temperature,which was CaCl₂+FA＞CaCl₂+HIDS＞CaCl₂＞CK.Compared with the control,the germination rate,germination potential,germination index and vigor index of summer squash seeds soaked in CaCl₂+FA solution increased significantly by 2.48%,2.48%,1.15% and 14.71%,while the root length,fresh weight and dry weight increased by 15.12%,46.47% and 13.35%;soaking seeds in CaCl₂+FA solution enhanced osmotic adjustment substances and antioxidant enzyme activity,and increased proline,soluble sugar,soluble protein contents,SOD,POD activities by 14.52%,180.00%,31.87%,1.52%,53.53%,respectively.The contents of superoxide anion radica and H₂O₂ decreased by 131.97% and 35.83% respectively.In conclusion,different combinations of CaCl₂ reagents could reduce the damage of low temperature on seed germination,and the combination of CaCl₂ and FA had the best effect.