As an efficient passive heat transfer device, Oscillating Heat Pipe (OHP) transfers heat by sensible and latent heat. Studies have shown that gravity has a strong effect on the operation of the OHP. The heat transfer performance has an extreme variation at different angles. Traditional structure OHP is unable to start in the horizontal direction. The same situation occurs in the negative vertical position the evaporator being above the condenser. This cause there's no gravity to assist the backflow to the evaporator. To develop the gravity-independent performance, a three-dimensional OHP with an uneven turn as the reservoir was conducted. For improving the unidirectional flow to promote liquid reflux to evaporation, the asymmetric heating mode was proposed. Experimental results show that the OHP herein can start in all orientations even in the negative vertical position. The stable pulsating flow of the working fluid can be achieved at different inclination angles. At low heating power of less than 300W, compared with other angle conditions the vertical position with the bottom heated has the best heat transfer performance. While at high power inputs above 300W, the OHP almost has the same heat transfer properties in all inclinations. Furthermore, the filling ratio is an important influencing factor. With a 50% filling ratio, OHP has the optimum heat transfer performance while a 70% filling ratio has better anti-gravity characteristics. The gravity-independent characteristic of OHP developed the scope of application.