The invention discloses a silicane thermolysis furnace with double-layer cooling jackets and a production process. The silicane thermolysis furnace is characterized by comprising a bell jar, a bottomplate, silicon rods, jacket cover plates, outer cooling jackets and inner cooling jackets. By arrangement of the double-layer cooling jackets outside the silicon rods, more cold energy can be providedfor the inner upper portion of the jackets through perforation of the upper portion of the inner jackets by cold air in a cooling gap between the double-layer jackets, so that temperature uniformityof inner upper and lower portions of the jackets is realized, and growth uniformity of the silicon rods is guaranteed. By a raw material gas inlet pipe for downward jetting of raw material gas, flowing in the furnace is enhanced, and local overhigh SiH4 concentration can be eliminated.