3D space handwriting is a gesture-like character written in the air, and it is a promising input method for its portability. In this work, we propose a practical development of 3D space handwriting recognition system by combining 2D handwriting and the ligature of 3D handwriting based on that the most different part between these handwritings is the shape of ligature. We designed a ligature model not to depend on each character shape but to depend only on incoming and outgoing vectors. Therefore with a few ligature models, various ligature shapes are modeled. By using 2D space handwriting models and data, we can use existing models for various writing styles, and overcome the problem of the lack of data.