In this article, we first analyze the limitations of the generic churn model through an user case story, based on that the churn model and marketing intervention system is proposed. This system not only forecast the churn of customers, the most importantly, it can provide the solution of how to intervene the customers and retain the customer. After all, retaining customers and creating market value at a reasonable cost is one of the most important purposes of building a churn model. In the second part, we analyze all the challenges in building a customer churn and how to find the optimal intervention action. In the last part, the solutions to these challenges are given out.