The invention discloses a lithium battery preheating and cooling system by employing a two-phase flow power-type separate heat pipe and relates to the technical field of battery heat management. The lithium battery preheating and cooling system comprises a lithium battery unit, a heat pipe working medium circulating pipeline, a central controller, a self-circulating heat pipe electromagnetic valve, a heat conversion unit and a power unit. The lithium battery preheating and cooling system has the beneficial effects that the use security and the cooling effect of a lithium battery are improved,and the problem of low performance of the lithium battery in low-temperature operation is solved, thereby prolonging the service life of the lithium battery.