In order to study the influence of refractive index profile structure on optical properties of G.657.B3 fiber, the refractive index profile with the depressed structure and the corresponding structural parameters (such as b/a value, c, Δnc- and Δn+) are designed. Meanwhile, appropriate vapor axial deposition(VAD) method, melting process and drawing conditions are used to improve the bending loss of the optical fiber and meet the requirements of cut-off wavelength, mode field diameter and low water peak. The optical fiber preform prepared by the optimized process is drawn and tested. The results show that the attenuation of the optical fiber decreases to 0.278 dB/km at the wavelength of 1383 nm, when the bending radius is 5 mm and one circle, the typical macro-bending loss are 0.081 dB and 0.188 dB respectively at the wavelength of 1550 nm and 1625 nm, which fully meet the requirements of ITU-T G.657.B3.