Abstract: The evanescent field intensity distribution of the fiber was analyzed both theoretically and experimentally(z=10 nm, 100 nm, 500 nm,1 000 nm), and the manipulation of micron fiber optical tweezers for microspheres was studied in experiment. In the experiment, a single-mode optical fiber with a diameter of 125 m was transformed into a tapered fiber with a 2 m diameter at the minimum waist. When the laser light was launched into the fiber, due to the evanescent field of the tapered fiber, the polystyrene microspheres with a diameter of 3 m could keep balanced state, and the nearby microspheres were attracted onto the fiber surface and rolled at the speed of 5.3 m/s in the direction of light propagation. This experiment traps the microspheres and verifies the mechanical effect of the fiber optical tweezers. The non-contact, non-destructive manipulation of fiber optical tweezers for microspheres has potential applications in the field of biosensors.