Abstract: Objective To investigate the effect of free forearm flap in the treatment of oral and maxillofacial defects after tumor resection. Methods The clinical data of 47 cases of oral and maxillofacial tumor patients in our hospital from January,2013 to December,2015 were retrospective analyzed.All patients were given tumor resection,and the defects were repaired by forearm flap.After the surgery,the flap survival rate,swallowing function,pronounce function complications were observed,also the changes of serum sialic acid (SA) and interleukin (IL)-2 levels before and after treatment were observed. Results All patients were treated with surgery at the first time and the repair treatment included excision,flap design,cut flap,anastomotic repair.The patients were followed up for 6 to 18 months;the flap survival rate reached 95.7%(45/47).After 1 month,the SA level of patients was (0.72±0.24) mg/L,which was significantly lower than before surgery (0.96±0.27) mg/L (P<0.05),and IL-2 level of patients was (13.94±4.12)μg/L,which was significantly higher than before surgery (5.69±1.38)μg/L (P<0.05).After 3 month,swallowing function:2 grade 9 cases (19.1%),3 grade 38 cases (80.9%).After 6 months,34 cases (72.3%) patients can clearly pronounce.The complications included:scar 14 cases (29.8%),pigmentation 39 cases (83.0%),itching 24 patients (51.1%),and skin abnormal feel 43 cases (91.5%). Conclusion The forearm free flap can treat oral and maxillofacial defects after tumor resection with satisfactory efficacy.The flap survival rate is high and swallowing function and pronunciation function is recovered well.