The invention relates to a preparation method for asbestos-free montmorillonites, which is characterized by comprising the steps of drying bentonite raw ore fully; adding water to the bentonite raw ore for dipping; stripping, dispersing and sieving the bentonite raw ore; dispersing further suspension fully; placing the suspension in a liquid storage tank; acquiring upper suspension after placing of the suspension; and drying the upper suspension. Therefore, the asbestos-free montmorillonite is prepared and safety of the montmorillonite is improved.