The modified asphalt used in permeable pavement generally adopts wet process, and the wet modified asphalt has good performance. However, with the application of wet modified asphalt, modified asphalt is facing some problems, such as easy segregation, high cost and difficult quality control. The application of direct injection modifier adopts dry process, which is mixed with aggregate first, and then asphalt and other materials are added to prepare asphalt mixture. The application of direct feed modifier avoids the shortcomings brought by wet process. In this study, 直投型高粘 direct feed modifier with excellent performance in all aspects is selected to use dry process for plant mixing of asphalt mixture, including the influence of dry mixing time and dry mixing temperature on mixture performance in indoor mixing, so as to guide the determination of plant mixing dry process. The asphalt mixture in the test project is selected for sampling and analysis to study the performance difference between the mixture prepared by plant mixing dry process and indoor mixture.