The invention provides a device special for separating impurities of crystal cotton fibers. The device is characterized by comprising a feed system, a beating separating system, a layering impurity removing system and a fiber collecting system which are disposed in sequence. The layering impurity removing system comprises a pipeline contracting gradually. The beating separating system is disposed at the large port of the pipeline contracting gradually. The small port of the pipeline contracting gradually is connected with a bend. A impurity removing opening is formed at the connection of the pipeline contracting gradually and the bend. The beating separating system comprises a plate type beating hand. The device is small in fiber damage and high in impurity removing efficiency.