Objective:STAT(signal transducer and activators of transcription) is one kind of cytoplasm transcription factor which plays an important role in promoting malignant tumor to genesis,proliferation and apoptosis. This research is to approach the association the single nucleotide polymorphisms(SNP)in STAT3 with biological behavior of gastric cancer. Methods:Using SYBR GREEN PCR with Tm-shift primers to detect genotyping of the SNP in STAT3 in 93 gastric cancer patients. Results:SNP in STAT3 of 18 gastric cancer patients,which confirmed by gene sequencing are same as the results by SYBR GREEN PCR with Tm-shift primers. Stratified analysis indicated that an elevated risk of vessel invasion and nerve invasion was observed in subjects who carried at least one G allete (GG or CG) compared with CC genotype (P < 0.001). Conclusion:SYBR GREEN PCR with Tm-shift primers can be one of the methods to detect STAT3 SNP. SNP in STAT3 was associated with clinicobiological behaviors of gastric cancer,such as vessel invasion and nerve invasion. The expression of STAT3 G allele indicates high risk of vessel invasion and nerver invasion.