The invention provides a heat balance semi-solid slurry preparation and extrusion processing automatic production line. The automatic production line is characterized by comprising a smelting furnace,a mechanical arm taking and injecting machine, a heat balance semi-solid slurry preparation device, a mechanical arm slurry conveyor and extrusion molding equipment; the smelting furnace, the mechanical arm taking and injecting machine, the heat balance semi-solid slurry preparation device, the mechanical arm slurry conveyor and the extrusion molding equipment are connected in sequence. The automatic production line can rapidly absorb superheat of melt in the center of the interior of a charging barrel, homogenize the temperature field of semi-solid slurry, overcome the defect of non-uniformcooling of slurry, guarantee the uniformity of the slurry structure and improve the quality of the slurry and castings. The automation degree, working efficiency and volume production capacity are improved. The process of industrialization of the metal semi-solid processing technology can be accelerated. The heat balance semi-solid slurry preparation and extrusion processing automatic production line is compact and reasonable in process design and flow layout, convenient to operate and capable of continuously, stably, safely and accurately completing the metal semi-solid processing technology.