A tension roller comprises a first roller (10) and a second roller (20). Roller surfaces of the two rollers (10, 20) both comprise a tension surface (12, 22) located at a center portion thereof and a holding surface (14, 24) located at two sides of the tension surface (12, 22). A roller diameter of a region where the tension surface (12) of the first roller (10) is located is thinned to less than a roller diameter of a region where the holding surface (14) is located, thereby forming a pressure reduction groove (15) outside and around the tension surface (12). The holding surfaces (14, 24) of the first roller (10) and the second roller (20) are opposite to each other. Also provided are a web material (30) suitable for the tension roller, and method for lossless transportation of the web material by using the tension roller. When transporting the web material (30) by using the tension roller, a defect on a structural surface will not be produced by contacting with the first roller (10).
