In this study, miR-1307-5p targeted TRAF3 to regulate the MAPK pathway, miR-1307-5p targeted to TRAF3 degraded TRAF3 protein and activated p-ERK1/2 and p-p38 proteins in the MAPK pathway to promote the proliferation of lung adenocarcinoma, while there was no significant change in ERK1/2 and p38 protein; however, inhibiting miR-1307-5p increased the protein levels of TRAF3 and inhibited the proteins p-ERK1/2 and p-p38 in the MAPK pathway to induce the apoptosis of lung adenocarcinoma, and there was no significant change in ERK1/2 and p38 protein. The gene discussed is TRAF3; the disease is lung adenocarcinoma.