Objective To investigate the correlation between the extent of gefitinib associated rash and the mutation of epithelial growth factor receptor (EGFR) in patients. Methods We selected 50 lung adenocarcinoma patients who received gefitinib treatment with rash in the period from May 2016 to May 2017, record the extent of skin rash and the mutation of EGFR site. The expression of EGFR was divided into 6 types, Include18 exon positive, 19 exon positive, 21 exon positive, 18 and 19 exon positive, 19 and 21 exon positive, 18 and 21 exon positive. use the Spearman Correlate find whether there was a significant correlation between the two. Results The Spearman Correlate show that there was no significant difference between the 6 types of skin rashes. Conclusion There was no correlation between the occurrence of rash and the expression of EGFR, the experimental error may be due to the small sample size. Later, by increasing the sample size, again to confirm it