Big data and programmatic buying is profoundly changing the ecology and competition pattern of China's media industry and advertising industry.The development and utilization of large data makes the advertisement communication more precise，personalized，real-time and visualized.Programmatic buying based on the big data has become the dominated form of transactions for China's online advertising market.This paper focuses on the basic principles and operational processes of advertising programmatic buying，the ecology and optimization of China's programmatic advertising industry，and the business strategy of China's programmatic advertising industry.