TEA CO2 and KrF excimer laser pulses, whose wavelength is 10. 6μm and 248nm, are used to remove coatings from SMF28 optical fiber. The relationship s between laser fluence, the number of pulses and the ablation depth of optical fiber coatings are investigated. It is shown that the ablation depth of fiber coatings increaseswith laser fluence and ultraviolet laser pulse numbers in logarithm way, while mountingwith infrared laser pulse numbers linearly. There exists an optimum value in 8. 15J /cm2 , 20 pulses and 452mJ / cm2 , 800 pulses using infrared CO2 and ultraviolet excimer laser respectively to obtain the naked fiber.