This study investigates the effects of brief mindfulness meditation (MM) on students’ attention and mood in online learning within a media multitasking environment. Previous research has shown MM’s positive impact on attention span in traditional classrooms, but its effectiveness in online learning remains understudied. Forty freshmen from Xi’an Jiaotong University were randomly divided into meditation and control groups. Participants underwent either a meditation or control intervention followed by an online learning course. The study employed scales, assessments, interviews, brain activity monitoring, and eye-tracking to measure mood changes and attention levels. Results indicate that short-term meditation significantly improves attention levels and positive mood, as evidenced by eye-tracking, EEG, and scales. A relationship between mood and attention was also observed in students’ post-learning performance. This research provides new insights into the effects of MM on mood and attention in online learning, contributing to education and psychology research.