Mutational spectrum of p53 gene was analyzed by polymerase chain reaction (PCR)-single strand conformational polymorphism (SSCP) and direct DNA sequencing technique in tissue specimens of primary non-small cell lung cancer (NSCLC) to study the action of p53 gene, its type of mutations and its possible relation to different carcinogens. Results revealed that mutation of p53 gene was found in 94 of 128 resected specimens of NSCLC, including point mutations in 86 cases, deletion and insertion in seven and mutation of the linking site in one, and 63.9 percent of point mutations were G-T and T-G substitution and 25.6 percent G-A and A-G. It suggested that p53 gene mutation correlated closely to the occurrence of NSCLC. Possible environmental carcinogens were discussed in the paper based on the characteristics of the p53 gene mutation.