The invention provides a micro heat pipe and a using method thereof. The micro heat pipe comprises a pipe shell and a gas-liquid baffle; the gas-liquid baffle divides the internal channel of the pipe shell into a gas-phase working medium channel flow and a liquid-phase working medium channel flow; the bottom surface of the pipe shell is a flat surface; the top surface of the pipe shell is an arc-shaped salient; and the gas-phase working medium channel flow is arranged above the liquid-phase working medium channel flow. According to the micro heat pipe, the flooding limit bottleneck of the heat pipe can be effectively prevented, thus the liquid-phase flowing resistance is relatively small; and the pipe shell and the baffle form a gas-phase channel flow profile with two sharp corners together, gas-liquid interfaces of working mediums are in the gas-phase channel flow, close to the two sharp corners of the profile, and form a wedged capillary structure with the gas-phase channel flow, and positive feedback is still effective.