Front running is relatively few discussed in Taiwan. This thesis explains what front running is and discusses impact on regulating it based on different insider trading theory from U.S. legal perspective. By using actual cases, it will be elaborated how to apply major insider trading theory to tackle front running. Based on U.S. law understanding, this thesis discusses whether front running can be attached to any criminal responsibility in Taiwan through case study and qualitative legal analysis. High frequency trading is a modern type of trading activities by leveraging computer network technology. One major type of high frequency trading relies on predicting other market participants’ trading activities and front-run them, which makes this type of high frequency trading similar to front-running. Up to now, no relevant judgment is rendered in Taiwan. This thesis first introduces how high frequency trading works in U.S and some U.S. court opinions in related cases. It will then be analyzed whether high frequency trading is illegal according to criminal laws in Taiwan. The current status and future of high frequency trading in Taiwan will be discussed as well.