Application on multi-platforms for a computer-aided fixture design (CAFD) system is significant. But now, relative less attention is focused on this direction. On above backgrounds, research was carried out on data construction, data description, data conversation as well as data parsing. In modular fixture system, components in the modular fixture base were described according to their CSG-based primitives. So, XML was used to represent the simple data because of its widely using on net and different operational systems. By developing interfaces between diverse CAD systems, the modular fixture system can be applied on heterogeneous environments and reinventing the wheel can be avoided.