In this study we give an analytical model for the Young-Laplace equation of two-dimensional (2D) drops under gravity. Inspired by the pioneering work of Landau and Lifshitz [Fluid Mechanics, 2nd ed. (Pergamon Press, Oxford, 1987), pp. 242–243], we derive general analytical expressions of the profile of drops on flat surfaces, which is available for arbitrary contact angles and drop volumes. We then extend the theoretical model to drops on inclined surfaces and reveal that the contact line plays an important role in determining the wetting state of the drops: (1) when the contact line is completely pinning, the rear and front contact angles and the shape of the drop can be uniquely determined by the drop volume, the slope of the inclined surface, and the contact area; (2) when the contact angle hysteresis is taken into consideration, various mathematical solutions of the wetting state exist for a drop of given volume on a given surface, but there is only one wetting state corresponding to a minimum free energy which results from the competition between the capillary force and gravity. Our theory is in excellent agreement with numerical and experimental results.