KLD-12 peptide with a sequence of AcN-KLDLKLDLKLDL-CNH(2) was synthesized and its biocompatibility was assessed in animals. Rabbit MSCs were cultured in the hydrogel for 2 weeks. Live cells were counted by using Calcein-AM/PI fluorescence staining. MTT was employed to assess the viability of MSCs cultured in KLD-12 peptide solution of 0.01%, 0.03%, and 0.05%. Hemolysis test, skin irritation test and implantation test were conducted to evaluate its biocompatibility with host tissues. Our results demonstrated that the MSCs in hydrogel grew well and maintained round shape. Cell survival rate was 92.15% (mean: 92.15%+/-1.17%) at the 7th day and there was no difference in survival rate between day 7 and day 14. Cell proliferation test showed that the A value of the KLD-12 solutions was not significantly different from that of control groups (complete culture media) (P>0.05) at the 24th and 48th h. The hemolysis rate of KLD-12 solution was 0.112%. Skin irritation test showed that the skin injected with KLD-12 solution remained normal and the score of skin irritation was 0. The histological examination with HE staining exhibited that the skin layers were clear and there was no infiltration with neutrophilic granulocytes and lymphocytes. It is concluded that KLD-12 peptide hydrogel had a good biocompatibility with host rabbit and MSCs, and KLD-12 peptide hydrogel can provide an appropriate microenvironment for MSCs.