Procrastination behavior is prevalent among nursing students in China. However, little research has examined how mindfulness is associated with procrastination behavior, via achievement motivation among nursing students. The aims of this study were to investigate the relationship between procrastination behavior, mindfulness and achievement motivation, and explore the mediating effect of achievement motivation on mindfulness and procrastination behavior of nursing students. A correlational cross-sectional study was performed using an online questionnaire. The study was conducted from January to March 2022 among 632 students from 1 university. A general information questionnaire, Achievement Motivation Scale, Five Facet Mindfulness Questionnaire and General Procrastination Scale (GPS) were used for investigation. Calculations were performed using SPSS Statistics, version 25. Descriptive statistics, correlation, and process plug-in mediation effect analyses were used to analyze the data. A total of 640 questionnaires were issued and 632 valid questionnaires were finally recovered, with an effective recovery rate of 98.75%. The GPS score of 632 nursing undergraduates was (55.80 ± 6.57), achievement motivation scale score was (−2.49 ± 8.73), Five Facet Mindfulness Questionnaire score was (118.21 ± 18.39). Achievement motivation and psychological capital were all negatively correlated with procrastination behavior (
r
= −0.291, −0.483;
P
< .01). Achievement motivation played a partial mediating role between mindfulness and procrastination behavior, and the mediating effect accounted for 59.82% of the total effect. The procrastination behavior of nursing undergraduates is at the middle level. Mindfulness can influence procrastination behavior through achievement motivation. Measures are needed to decrease the procrastination behavior by developing mindfulness programs to increase their achievement motivation.