Abstract: A method for forming a mat includes forming a fixer made of a rigid material. The fixer includes a central portion which is cylindrical and which includes an annular wall having two ends opposite to each other. A mold assembly is provided for forming the mat. The fixer is disposed in the mold assembly in an open state. The mold assembly is closed, and a soft plastic material for forming the mat is filled into the mold assembly. The soft plastic material envelopes a peripheral portion of the central portion of the fixer. Then, the mold assembly is opened to remove the mat and the fixer which are fixed together.