〔Abstract〕 Objective To explore the therapeutic effect of early low-frequency electrical stimulation on knee extension contracture and its possible intervention mechanism in rabbits. Methods Twenty-four New Zealand white rabbits were randomly divided into control group(C), electrical stimulation group(E), natural recovery group(NR) and electrical stimulation treatment group(EST), with 6 rabbits in each group. Group C had free activity for 7 weeks. In group E, free activity was performed for 4 weeks, followed by low frequency electrical stimulation on the quadriceps of the left hind limb for 3 weeks. In group NR, the left knee joint was fixed in the straight position for 4 weeks, and then 3 weeks of free activity was given after the fixed removing. In the EST group, the left knee joint was fixed in the straight position for 4 weeks, followed by low frequency electrical stimulation on the quadriceps of left hind limb for 3 weeks. After each group intervention, the range of motion(ROM) of the left knee joint was measured before and after muscle removal. HE staining and Masson staining were performed on the rectus femurs. The protein expression levels of transforming growth factor-β1(TGF-β1) and α-smooth muscle actin(α-SMA) in rectus and capsule were detected by Western blot. Results Compared with NR group, total contracture and myogenic contracture of the knee joint were reduced(P<0.01) and arthrogenic contracture was not improved in EST group. HE staining of rectus femoris showed that the shape and membrane integrity of muscle fibers in the EST group were improved compared with those of the NR group. The quantitative analysis of masson staining showed that the fibrosis improvement degree of rectus femoris in the EST group was higher than that of the NR group( P<0. 01). In addition,the expression levels of TGF-β1 and α-SMA in the rectus femurs of EST group were lower than those in the NR group( P<0. 05). The expression differences of TGF-β1 and α-SMA in joint capsule of the EST group were not statistically significant compared with those in the NR group( P>0. 05). Conclusion Early lowfrequency electrical stimulation can improve extension contracture of the knee via reducing the level of skeletal muscle fibrosis. The inhibition of skeletal muscle fibrosis is greater than that of joint capsule fibrosis.