The research on new organic cultivation substrates using biogas residue as the main raw material is of great practical significance for further efficient utilization of biogas fermentation residues and sustainable agricultural development. This study used cucumber seeds as experimental materials and mixed biogas residue with peat，vermiculite，and perlite in a certain mass ratio to form four composite matrices. The physical and chemical properties of the mixed matrices and their effects on the growth of cucumber seedlings were studied using commercial matrix as a control(CK). The results showed that:(1)The bulk density range of different formulations of biogas residue matries varied from 0.19 to 0.22 g/cm3，all of them were significantly lower than that of CK. The electrical conductivity ranged from 1.58 to 2.15 mS/cm，with treatments GS2，GS3，and GS4 showing significantly higher conductivity than CK. The total porosity ranged from 60.30% to 68.65%. The pH value and ammonium nitrogen content of the mixed substrates were both significantly higher than CK，while the organic matter and available phosphorus content ranked as:GS4>GS3>GS1>CK>GS2 and GS2>GS1>GS3>CK>GS4，respectively.(2)The cucumber seedlings grown in different formulations of biogas residue substrates had higher plant height，leaf area，root volume，above-ground fresh weight，underground dry weight，total fresh weight，and total dry weight than CK，with treatment GS3 showing the highest germination rate，plant height，stem thickness，above-ground fresh weight，total dry weight，seedling vigor index，and growth function(G) value，which demonstrated a clear growth advantage，compared to other treatments.(3)Principal component analysis analysis indicated that the plant height，stem thickness，leaf area，and above-ground fresh weight of the seedlings were positively correlated with ammonium nitrogen，available phosphorus，pH value，and electrical conductivity. Root volume was positively correlated with air-water ratio and ammonium nitrogen. Underground fresh weight was negatively correlated with water-holding porosity and water-holding capacity. Mantel analysis showed that the seedling vigor index and G value were mainly influenced by ammonium nitrogen，bulk density，total porosity，water-holding capacity，and electrical conductivity.(4)Through comprehensive evaluation，it was found that treatment GS3 had the highest comprehensive evaluation index(0.61)，indicating the best overall growth condition of the cucumber seedlings. In conclusion，partially replacing peat with biogas residue in cucumber seedling cultivation could effectively improve the quality of cucumber seedlings，with the G3 treatment providing the best quality of cucumber seedlings.