The capillary flow in interior corners of infinite long cylinder under microgravity environment is investigated by the homotopy analysis method (HAM). Different from other approximate computational method, the HAM totally depends on small physical parameters, and thus it is suitable for most nonlinear problems. The HAM provides us with a great freedom to choose basis functions of solution series, so that a nonlinear problem can be more effectively approximated. The HAM can adjust and control the convergence region and the convergence rate of the series solution through introducing auxiliary parameter and the auxiliary function. The computed result indicates that this method has the advantage of high accuracy.