This invention provides an anti-off invisible sock and a manufacturing method thereof. The anti-off invisible sock includes a sock body and an anti-slip film. The sock body includes a sock heel, a sock middle section, and a sock toe. The sock heel, the sock middle section, and the sock toe are formed integrally by knitting. The anti-slip film is hot stamped inside the sock heel by heat transfer and it is a polyolefin glue film. The anti-off invisible sock provided by this invention has sufficient elasticity, more closely fitting, and is comfort to wear and uneasy to fall off. Meanwhile, an allergic problem caused by silica gel in the conventional anti-off sock can be effectively avoided.