Abstract: The curved free surface of liquid in a cylindrical tank caused by surface tension under low-gravity environment is considered. The dominant modal vibration function of liquid sloshing under pitching excitation is selected as the basic function of velocity potential. The generalized state equation of liquid sloshing system is introduced by expanding the lateral sloshing boundary condition of the free surface to a Fourier-Bessel series, and the formulas of sloshing characteristics including wave height, sloshing frequencies, sloshing force and sloshing moment are also deduced, respectively. Through numerical calculation, the dynamic responses of sloshing characteristics are studied when the tank under pitching excitation. And the convergence, applicability and correctness of the present algorithm are validated.