In this research, we review the relevant literatures to discuss the predictability of foreign exchange rates. Besides, we collect literatures to examine the development of the fundamental models, market models, technical analysis and trading rules and compare and evaluate the precision of these models. Moreover, we make a case study of a global leading investment bank to discuss how to use these models in practice. The result shows that fundamental models can help to establish the long-term equilibrium but have some shortcomings and thus we could adopt market models to resolve the shortages and the technical analyses and rules to set the exact price levels for trading purposes.