A JGD-type single-crystal laser furnace produced by China Electronics Technology Chip Research Institute is a single-crystal furnace with automatic diameter control for upward weighing, which helps realize fully automatic intelligent growth control of crystal-pulling methods. The JGD Czochralski crystal furnace control software uses a mathematical model for Czochralski crystal growth. The entire process of crystal growth is based on the mathematical model, and real-time closed-loop feedback control is achieved using a crystal weight as the control variable. This software employsfour-segment and arbitrary multi-segment crystal mathematical models. The former model embodies the concept of smooth transition between the seed crystal, shoulder, and equal-diameter segments in the design of the shoulder segment, and the latter model is more flexible and diverse in curve design, making crystal mathematical model design more convenient. The crystal mathematical model of the JGD single-crystal furnace control software is widely used in various crystal growth processes including those of InSb, YAG, and other crystals. The crystal shape is well controlled and of excellent quality.