Real Time Bidding(RTB)is emerged with the rise of Internet and big data,and it realized precision marketing through the market segmentation strategies of Demand Side Platforms(DSPs).This paper studies DSPs strategies for market segmentation,and established a market segmentation model to find the optimal granularity.We proposed to validate our model using a computational experiment approach,and the experimental results show that with the increasing of the market segmentation granularity,the total revenue has a tendency of a rise first and followed by a decline.