Botulinum toxin type A (BTX A) has gain widespread use in various neurological conditions, characterized by safe injection and less side-effect. This review will examine the current research of BTX A in the following aspects: mechanism, location, dose and outcome, which manifests the safety and efficacy data of BTX A injection treatment to the symptoms of Parkinson disease, including refractory tremor, focal dystonia, loss of postural reflexes, sialorrhea, gastrointestinal symptoms and depressive disorder.