The present invention provides a lithium ion battery including a lithium ion battery body. The lithium ion battery body includes a positive electrode sheet, a separator, a cushion rubber and a solid-state negative electrode sheet. The positive electrode sheet and the solid-state negative electrode sheet are provided at upper and lower surfaces of the separator. The cushion rubber is located in the positive electrode sheet and the separator. The present invention further provides a method for preparing a lithium ion battery including the preparation of the positive electrode sheet, the preparation of the solid-state negative electrode sheet and the preparation of the cushion rubber.