Background. Flow is characterized by the strong concentration in competitions, eliminating irrelevant thoughts and emotions, integrating all tasks, and continuing the competition smoothly even in challenging situations. The present study was into whether or not brief mindfulness training can improve athletes’ flow and further explore the mediating effect of resilience in the intervention. Methods. The 2 (experimental conditions) × 2 (time) mixed design was used in this study. Fifty-seven student-athletes were recruited and randomly assigned into either a brief mindfulness group (n = 29) or a control group (n = 28). Before and after the intervention, every participant completed a self-report measure including mindfulness, flow, and resilience. Results. Participants in the brief mindfulness group showed increased mindfulness, flow, and resilience (
p
<
0.001
) after brief mindfulness training; when putting resilience change (B = 0.30, 95% CI [0.031, 0.564]) into the equation, the direct (95% CI [3.156, 13.583]) and indirect (95% CI [0.470, 5.048]) effects of mindfulness training were both significant. Conclusion. It was concluded that brief mindfulness training could significantly improve athletes’ flow and resilience, and resilience partly mediated the effects of brief mindfulness training on flow.