A novel method for the design and fabrication of heterogeneous objects is presented, which combines the Three Dimensional Printing (3DP) and micro droplets dispensing technology. It provides a solution to the fabrication of assemblies with multi materials, which can not be fabricated by traditional processes. An integrated design and fabrication system for heterogeneous objects based on the new process is introduced. Its constructive representation scheme is described. To show the effectiveness of the working process of multi-materials, based on slice software of color STL model and developing prototyping system, an example is shown to illustrate the entire design-fabrication cycle for heterogeneous objects.