Abstract: In this work, water adsorbed in single-walled carbon nanotube (SWCNT) is simulated by the Grand Canonical Monte Carlo (GCMC) method. The effects of pore length, pore size and surface strength on water adsorption behaviors at 298 K are systematically studied, via the characterization of isotherms, local density distribution and isosteric heat. There are hysteresis loops observed for water adsorbed and desorbed in SWCNTs with relatively large pore radii (PR=0.8, 1.0 nm), and the hysteresis loop disappears as the pore radius decreases to 0.55 nm. In addition, the water molecule packing manners are in the arrangement form of single chain, double helix chain and water clusters due to the pore size effects. When the pore length is in the range of 4~8 nm, the initial adsorption pressure becomes smaller and smaller as the pore length increases, but this effect rule gradually disappears with increasing pore length to 10 nm. Finally, the initial pressure of water adsorption decreases with surface strength; and when surface strengths are 20, 28, 32 K, the capillary evaporation phase transitions completed instantaneously. While the surface strength increases to 40 K, the capillary evaporation phase transition is shown gradually desorbed steps. As surface strengths increased from 20 K to 40 K, the isosteric adsorption heat at the pressure points of capillary condensation phase transition is 127.47, 117.98, 84.04, 59.16 kJ·mol^-1, respectively.