The invention discloses a child bicycle suitable for children at many ages. The child bicycle comprises a bicycle body; back wheels are pivoted to the back end of the bicycle body, a front wheel frame is connected to a rotating shaft at the front end of the bicycle body, and a front wheel is connected to a rotating shaft on the lower portion of the front wheel frame; the bicycle body is further provided with a first back chair and a second back chair which is detachably connected to the first back chair; by means of the detachable back chairs, the function of adjusting of different heights of the back chairs can be achieved, and accordingly the child bicycle suitable for heights of children at different ages can be provided for the children.