Disclosed are a 3D image system and 3D glasses. The 3D image system includes a liquid crystal display monitor and the 3D glasses. The liquid crystal display monitor includes a backlight module and a ½λ wave plate. The ½λ wave plate converts lights from by the backlight module into linear polarized lights. The 3D glasses includes a first ¼λ wave plate for receiving and converting the linear polarized lights from the ½λ wave plate into circular polarized lights, a second ¼λ wave plate for converting the circular polarized lights from the first ¼λ wave plate into linear polarized lights, and a second ¼λ wave plate for filtering the linear polarized lights from the second ¼λ wave plate and transmitting the filtered lights to left and right eyes correspondingly. The present invention saves the cost and decreases the maintaining expense.