The study of today's cyber-physical system (CPS) has been an important research area. Internet data centers (IDCs) are energy consuming CPSs that support the reliable operations of many important online services. Along with the increasing Internet services and cloud computing in recent years, the power usage associated with IDC operations had been surging significantly. Such mass power consumption has brought extremely heavy burden on IDC operators. While most previous work only consider about dynamical optimization of IDC under electricity markets, the reaction of IDC toward electricity market has been overlooked. Due to the fact that IDCs are usually large-volume users in the electricity market, they might have market power to affect the electricity price. In this paper, we study how to address the challenge of interactions between IDC operation and electricity market price. To this end, we propose a supply function to model the market power of IDC and formulate a total electricity cost minimization problem as a non-linear programming. Then we present CMC algorithm inspired by the economics concept. CMC algorithm not only solves the optimization problem efficiently, but also uncovers the impetus of the work load distribution. Extensive performance evaluations demonstrate that the proposed method can effectively minimize the total electricity cost of IDCs by adaptively handling the interaction between IDCs and smart grid.