 Subjects will receive a single treatment session of intramuscular HengLi 200U or 240U if thumb spasticity is present or placebo after they first enroll the core phase randomly. Totally 180 subjects will be recruited in this part. Each completed subject should finish 8 visit 0 to 7 clinic visits. Subjects will receive a single intramuscular treatment with either HengLi or placebo at day 0 visit 0. The else 7 visits are at week 1, 4, 6, 8, 12, 16 and 18 visits 1 to 7 and week 6 visit 3 is appointed as the primary visit to determine efficacy. 