Objective To investigate the effect of oral fish oil on wound healing and related indexes in patients with diabetic foot ulcer(DFU).Methods A randomized,double-blind,placebo-controlled design was used to recruit 68 patients with DFU aged 18-80 years old in the hospital,and the baseline clinical data of the patients were collected.The patients were randomly divided into experimental group(32 cases,fish oil soft capsule,3 g/d)and control group(33 cases,corn oil soft capsule,3 g/d)by random number generated by Ex-cel,and the intervention lasted for 12 weeks.The primary endpoints included the proportion of complete wound healing and healing area≥50%.The secondary endpoints included wound area,healing time,inflamma-tion index,glucose metabolism index,nutrition related index and wound reinfection.Additionally,the influen-cing factors of wound healing were analyzed.Results After intervention,the proportion of complete wound healing and healing area≥50%in the experimental group was significantly higher than that in the control group(P=0.007,0.039).In the subjects with complete wound healing,the mean healing time in the experi-mental group was shorter than that in the control group,but the difference was not statistically significant(P=0.132).The reduction area of wound area in the experimental group was significantly larger than that in the control group(P=0.045).The decrease of interleukin(IL)-6 and IL-8 in the experimental group was significantly higher than that in the control group(P<0.05).There was no significant difference in the reduc-tion of C-reactive protein(CRP),tumor necrosis factor-α(TNF-α),neutrophil-to-lymphocyte ratio(NLR),glycated hemoglobin A1c(HbA1c)and platelet-to-lymphocyte ratio(PLR)between the two groups(P>0.05).The improvement of prealbumin(PA)in the experimental group was higher than that in the control group,but the difference was not statistically significant(P>0.05).Multivariate logistic regression analysis showed that oral fish oil intervention(OR=6.771,95%CI:1.787-25.652),HbA1c(OR=4.149,95%CI:1.026-16.770)and ulcer type(OR=4.319,95%CI:1.026-18.173)were the influencing factors of wound healing(P<0.05).Conclusion Oral fish oil promotes wound healing in patients with DFU,which may be re-lated to improving the level of chronic inflammation in the body.