Molecular dynamics simulations were carried out to study the influence of electrostatic field with different strengths and directions on the adsorption of phenol on single-walled carbon nanotubes (SWNT). It is examined in term of the structural parameters, the self-diffusion coefficients and the interaction energy. The results show that with the increase of electrostatic field strength, the number of phenol around SWNT increases, the hydration between phenol and coordinated water molecules decreases, the phenol-phenol's interaction increases, the SWNT-phenol's interaction energy increases, the water-phenol's interaction energy decreases and the self-diffusion coefficient of phenol and water decreases. Furthermore, comparing with the electrostatic field perpendicular to the central axis of SWNT, the electrostatic field along the central axis of SWNT can make more obvious effect to the parameters of system. The simulations results provide useful guidance for understanding the influence of electrostatic field on the adsorption of phenol on SWNT.