The specific year is different, the grades are different, and the subjects are different, corresponding to different test questions, such as: Sichuan Big Data Precision Teaching Alliance 2020-202 1 school year, the second unified monitoring of science mathematics. In terms of proposition, the joint entrance examination creates original evaluation questions according to the college entrance examination standards, and carries out the professional process of original proposition, grinding and examination. The test questions are based on the teaching materials and syllabus, reflecting the latest changes in the college entrance examination reform and conveying the latest spirit and concept of the college entrance examination reform. In the post-examination service, the joint examination adopts the form of online marking, and cross-marks all school papers. At the same time, the use of big data technology to generate multi-dimensional analysis reports and high-frequency wrong questions special training for students has promoted teachers' accurate teaching and individualized teaching, and also met students' learning needs for right and wrong questions and questions after the exam, improving and continuing the follow-up service of the joint exam. This kind of examination has changed from a simple examination behavior to an important part of scientific preparation and effective improvement of teaching.