Abstract: Objective: To study expression and clinical significance of urokinase type plasminogen activator （uPA） and its receptor （uPAR） in gastric cancer and their surrounding tissues. Methods: We detected uPA and uPAR expression levels on quantitative and parallel bases, by cDNA-mRNA dot blot hybridization in 23 gastric cancers and their surrounding tissues. Results: As shown in the hybridization results, 18 out of 23 had higher uPA mRNA expressions than their relevant surrounding tissues. Similarly, 19 out of 23 having higher uPAR mRNA expression. Both uPA and uPAR mRNA expression for 14 out of 23 being over 4 times higher than that of surroundings. The uPA and uPAR mRNA expression levels in gastric cancer tissues with lymph node metastases and infiltrated in muscular layer and serosal layer were obviously high. The uPA and uPAR mRNA expression levels in gastric cancer tissue of stage Ⅲ and Ⅳ were much higher than those of stage Ⅰ and Ⅱ. Conclusion: It suggested that the uPA and uuPAR mRNA expression shows a tendency to increase in mRNA transcription level in gastric cancer tissues; uPA and uPAR mRNA expression increased in gastric cancer tissues with invasion and metastasis. As a rdsult, it shows that the high expression of uPA and uPAR gene is an important factor affecting gastric cancer invasion and metastasis.