Task Performance is greatly significant in the field of education. The OECD defines Task Performance as the ability to function based on conscientiousness in the "Big Five" personality domains. People with high Task Performance tend to also have significant conscientiousness. In other words, they are more self-controlled, more responsible, and more persistent. As a result, they focus well on tasks and earn better grades. Task Performance includes self-control, responsibility, and perseverance. The study surveyed 3,647 10-year-old students and 3,621 15-year-old students in Suzhou (China) on their Task Performance by using self-assessment questionnaires, parent surveys, and teacher evaluation. The main results of the study are presented: (1) The overall status of task performance; (2) Predictive variable analysis of task performance; and (3) Task performance and life. [For part II, see EJ1324085; for part III, see EJ1324104; and for part IV, see EJ1324107.]