NFV is a new network concept that moves network functions from network appliances to virtual machines. Users can customize their own services by setting ordered traffic paths through network function virtual machines they want. Though this idea is flexible and scalable, it brings additional growth in east-west traffic. In this paper, we focus on NFV deployment in data center networks. An user has multiple VMs in a data center and wants to have some network functions for these VMs. According to the user's requirements and traffic flows, we design a heuristic NFV deployment algorithm for VNF allocation, VNF placement and traffic dispatching. We set a traffic model and evaluate our algorithm by simulation. We also give some further research directions in this paper.