This is a randomized, open-label, controlled trial along 24-weeks trails. Referred sample of adult subacute stroke patients (within 6 weeks since stroke, n=30) with mild spasticity of calf muscle will be included. Patients were randomly allocated to BoNT-A treatment group (15 patients) and control group (15 patients). In BoNT-A treatment group patients received 200 units BoNT-A injection in the triceps surae (150iu) and tibial muscle posterior (50iu). No special treatment was performed in the control group. Both groups received comprehensive rehabilitation for 8 weeks. Lower limbs Fugl-Meyer (FM) score, calf muscle modified Ashworth scale assess (MAS), gastrocnemius surface electromyography (sEMG) evaluation and modified Barthel index (MBI) were assessed before and 8, 12, 24 weeks after treatment. Gait analysis (step length，cadence，speed), 6-min walking distance were assessed 8, 12, 24 weeks after injection.