MiR-15a increased and Cdc42 decreased in the CD AC group compared to the control group (<i>P</i> < 0.05). miR-15a decreased and Cdc42 increased in the CD RE group compared to the CD AC group (<i>P</i> < 0.05). miR-15a was positively correlated with the Pediatric Crohn's disease Activity Index (PCDAI) (<i>P</i> = 0.006), while Cdc42 was negatively correlated with PCDAI (<i>P</i> = 0.0008).