This paper proposes a tilt sensor made by MEMS technology. The sensor consists of an electrode glass a small mercury drop a circular channel and a cover glass. The mercury drop is used as medium of a current flow and in contact with two circular chromel electrodes used as an angular-motion resistance When this sensor inclines the mercury drop inside the circular channel moves into the bottom under the influence of gravity. A tilt angle can be measured by changed resistance as tilting this sensor, This sensor has a linear section between +50.$^{circ}$ and -50.$^{circ}$ with the accuracy of 2.$^{circ}$. We are also studying about the enlargement of the linear section and the effect of the size of the mercury drop