Abstract: Objective 　To investigate the expression of FHIT gene in lung carcinoma and its relationship with differentiation degree and histological types and the expression of p53 gene. Methods 　The expressions of FHIT and p53 were detected by immunohistochemistry method and tissue microarray technique in the specimens of 110 lung carcinoma and 25 benign lung lesions. Results 　①Abnormal expression rate of FHIT was 16 % in benign lung lesions, 85. 5 % in lung carcinoma, the difference was very significant between them( P < 0. 01) ; when the differentiation degree was different, the difference of FHIT expression in the lung carcinoma was very significant ( P < 0. 01), and FHIT expression was positive correlation with differentiation degree ( r = 0. 608, P < 0. 01) ; when the histological types were different, the difference of FHIT expression in the lung carcinoma was not statistical significance ( P > 0. 05) ; ②comparing the negative expression group with the positive one of p53, the difference of FHIT expression in the lung carcinoma was not statistical significance ( P > 0. 05) ;in lung carcinoma abnormal expression rate of p53 was 53. 6 %, abnormal expression rate of FHIT was 85. 4 %, the difference was statistical significance ( P< 0. 01) ;the rate of union detection was 93. 6 %. Conclusion 　①FHIT protein may become the molecular maker of earlier period diagnosing of lung carcinoma, and the union detection of FHIT, p53 protein will help to improve the detection rate ; ②FHIT protein influences direction of differentiation of the lung carcinoma cell, and this will offer new thinking for the development of clinical tumour drug.