Eligible patients will be randomized on day 1 to receive double-blind treatment with Botulinus Toxin Type A for Injection (HengLi®) 100U or placebo in a 2:1 ratio. A total of 216 subjects will be randomized into this study. Followup visits will occur at day 0, week 6 and 12, and week 14, 18 and 24 thereafter until study exit at week 24 unless re-treatment was necessary. The primary efficacy variables is the change from baseline in the daily average frequency of micturition at week 6. After a screening period of 1 week, all eligible patients will be randomized to receive a single intramuscular treatment with Botulinus Toxin Type A for Injection (HengLi®) or placebo at day 0 (visit 0).