A composite floor comprises a coextrusion layer compression molded using a coextrusion process. The layer comprises a first stone-plastic layer, a stone-plastic foaming layer, and a second stone-plastic layer sequentially arranged from top to bottom. The stone-plastic foaming layer is used as the main material layer, which reduces a whole weight of the floor; and the first stone-plastic layer and the second stone-plastic layer are arranged at two sides of the stone-plastic foaming layer, respectively, so that the composite floor is more stable. It is more environmentally friendly and simple in manufacturing to use the coextrusion process for compression molding by avoiding bonding using glue. Use of the coextrusion process makes various layers bond more compact, with little delamination and warpage due to effect of environmental changes. The composite floor has a low expansion rate and shrinkage rate, excellent in performance and long in service life.