A modularized composite crystal preparation system comprises a furnace frame, a furnace chamber, a crystal growth temperature field module, a rotary lifting and weighing unit and a lifting mechanism.The furnace chamber is arranged on the furnace frame, the front side of the furnace chamber is provided with a front door, the lateral side of the furnace chamber is provided with a light-permeable window, the crystal growth temperature field module is arranged in the furnace chamber, the rotary lifting and weighing unit is arranged on the upper portion of the furnace chamber, the lower portion ofthe rotary lifting and weighing unit is connected with a lifting rod, and the crystal growth temperature field module is one of a micro-pulling-down module, a lifting module and a laser base heatingmodule. The system is a multi-purpose system, a body portion is universal to different crystal growth methods, convenience in replacement of the crystal growth temperature field module is achieved, crystal growth in different methods is realized, different types of functional crystals can be prepared, exploratory development of universities and scientific research institutions on multiple varieties of crystals can be met, and growth demands of small-batch crystals in industrial production can be met.