The present invention discloses an automatic zone melting crystal growth method and system. The method comprises the following steps: during an automatic diameter increasing stage, if a diameter of a single crystal is greater than a lower base surface diameter of a certain layer of truncated cone-shaped growth region and less than an upper base surface diameter thereof, then determining a growth region of the single crystal to be said layer of truncated cone-shaped growth region, and growing the single crystal in the growth region having a pre-configured growth parameter, wherein the growth parameter at least comprises a polycrystal dropping rate and a heating power; performing, according to a pre-configured function relationship, adjustment to grow the single crystal according to a pre-configured growth angle for the growth region of the single crystal, wherein the growth angle is defined as an included angle between a cone generatrix and a lower base bottom surface; and if the diameter of the single crystal reaches a target value, then switching to an automatic constant diameter growth stage, wherein the current growth region of the single crystal is in a topmost layer of growth region, and the single crystal grows along an axial direction in said growth region. A single crystal grown using the present invention has a predictable shape.