Comparative analysis has been performed on the mechanical properties of hollow and solid polyester monofilament with identical external diameter. Tensile test of hollow polyester monofilament was conducted to study the influence of hollow core and the manufacturing method on the tensile fracture mechanism of hollow monofilament. The compressive properties of hollow monofilament were determined to provide a bundle-compression method to study the behavior of hollow polyester monofilament under axial compressive loading and compare with solid one. The results show that the tensile property of the hollow monofilament has smaller breaking force and higher breaking elongation than solid monofilament in case of identical external diameter. Under compression loading, the solid monofilament show better compressive properties than hollow one with identical diameter. The hollow core only affects the values of compressive strain and stress, but it has no effect on the compression and deformation mechanism. The study results also show that the polyester monofilament can show better mechanical properties than the solid polyester monofilament for the same weight. This study can help to design the lighter textile materials with the hollow polyester monofilament.