From the process of sedimentation the mathematical relationship between deposition volume and powder properties as well as sedimentation parameters was deduced in this paper. The relationship was expressed by using indirect method. Based on the formula, design model and prediction model were set up. The models can be used to design powder properties and predict the volume fraction of FGM. Programs to solve the models were developed in numerical methods. As examples, TiC-Ni system FGM were designed and predicted. The prediction results fit well with the design. Experiment of Mo-Ti system FGM was used to validate the prediction model.