EDC was added to the universal adhesive Single Bond Universal to configure the experimental adhesives containing different concentrations （0.1，0.2 and 0.3 mol·L^－1 ） of EDC.The L-929 fibroblasts in the logarithmic phase were divided into negative control group and 0，0.1，0.2 and 0.3 mol·L^－1 EDC groups， and blank control group （culture medium） was set up；the L-929 cells in negative control were added with culture solution，and the adhesive film was prepared and the extract was obtained in different concentrations of EDC groups .The extract was co-cultured with the cells.The relative growth rate （RGR） was measured by CCK-8 method， and the cytotoxicity was graded.The freshly extracted third molars without caries were selected to prepare the micro-tensile bonding specimens. The universal testing machine was used to test the immediate（the specimens were stored in 37 ℃ deionized water for 24 h ） and aging（the specimens were treated in the hot and cold cycle machine for 5 000 times of circulation） micro-tensile bonding strengths of the specimens in various groups.The immediate micro-tensile test included control group （without EDC） and 0.1， 0.2 and 0.3 mol·L^－1 EDC groups，and the aging micro-tensile test included control group （without EDC）， and 0.1 and 0.2 mol·L^－1 EDC groups.The fracture mode of the specimens was observed with a stereo microscope.

In the cytotoxicity experiment， the RGR of cells in various group at 24， 48 and 72 h after co-cultivation were all above 75%，and the cytotoxicity was level 1. In the immediate micro-tensile test， the bonding strengths in control group and 0.1， 0.2 and 0.3 mol·L^－1 EDC groups were （30.71±4.36）， （39.41±6.72）， （26.51±9.54） and（18.55±5.37） MPa.Compared with contol group，the bonding strength in 0.1 mol·L^－1 EDC group was significantly increased （P<0.05），the bonding strength in 0.3 mol·L^－1 EDC group was significantly reduced （P<0.05）. The fracture mode observation results showed that the interface failure was the main performance in control group， 0.2 and 0.3 mol·L^－1 EDC groups，and the mixed failure was the main performance in 0.1 mol·L^－1 EDC group. In micro-tensile test，the bonding strengths in control group，0.1 mol·L^－1 EDC group and 0.2 mol·L^－1 EDC group were （21.42±1.58）， （35.70±1.17）， and （16.24±3.27） MPa， respectively， Compared with control group， the bonding strength in 0.1 mol·L^－1 EDC group was significantly increased （P<0.05），and the bonding strength in 0.2 mol·L^－1 EDC group was significantly reduced （P<0.05）. The fracture mode observation results showed that the interface failure was the main performance in control group and 0.2 mol·L^－1 EDC group， and the mixed failure was the main performance in 0.1 mol·L^－1 EDC group.

The experimental adhesive containing 0.1 mol·L^－1 EDC after added with EDC to the Single Bond Universal has no obvious cytotoxicity， and the immediate and aging micro-tensile bonding strengths are improved.