OBJECTIVE: To study the therapy effect of improved bilateral tibia lengthening. METHODS: From May 1997 to May 2000, 32 patients (varus knee deformity in 8 cases) with low stature were adopted in this study. Among them, there were 26 females and 6 males, aged from 18 to 45 years old. Operative procedures included: 1. tibia osteotomy 1 cm distal from tibia tuberosity and fibula osteotomy 10 cm proximal from lateral malleolus; 2. fixation of the tibia osteotomy with interlocking nail and locking the proximal nail; 3. fixation of the lengthening apparatus; 4. lengthened bilateral tibia 0.7 mm per day; 5. removed the apparatus and locked the distal nail 2 weeks later after limb lengthening was over. RESULTS: The mean distance of lengthening was 8.5 cm (ranged 3.5 to 12.0 cm), the mean duration of lengthening was 128 days(ranged 53 to 180 days), and the mean time of bone union was 180 days (ranged 120 to 270 days). Followed up for 1 to 3 years, 98% patients felt satisfactory in lengthening, gait and joint movement. CONCLUSION: The improved bilateral tibia lengthening technique is recommended for advantage of short time of bone union, less complication and correcting the varus deformity of knee simultaneously.