Chlorinated hydrocarbons are widely detected in groundwater, but the conventional methods for their removal are not economical both in time and in cost. This paper deals with the factors affecting the removal of PCE bynano-Ni/Fe. The data shows that the reaction rate of the unexposed nano-Ni/Fe is 4 times larger than the exposed one. Temperature is one of the important affecting factors. The reaction rate constant will increase by 2～3 times with the elevation of temperature by 10℃. Under certain conditions, the larger the percentage of Ni on the iron, the faster the dechlorination reaction. Nevertheless, 8% is the best amount for dechlorination. Dissolved oxygen in solution is not helpful to the removal of chlorinated hydrocarbons.