A disk structure is disposed in an optical tweezers device including a light source for producing incident laser light. The disk structure includes a first substrate, a second substrate and a reflective layer. The second substrate is disposed with respect to the first substrate. One of the first substrate and the second substrate has at least one flow path. The reflective layer, which is adhered to the second substrate, is disposed between the first substrate and the second substrate. After the incident laser light passes through the first substrate and then reaches the reflective layer, the incident laser light is reflected back as reflective laser light by the reflective layer to form reflective laser light. A tweezers light field is formed in the flow path by both the reflective laser light and the incident laser light.