Objective To investigate the expression level and methylation level of micro RNA-34b（miR-34b） gene in papillary thyroid carcinoma （PTC）， and to analyze the relationship between methylation and clinicopathological characters of PTC. Methods PTC tissues and tumor adjacent tissues were collected from 25 patients with PTC who underwent operation in Huai’an First People’s Hospital of Nanjing Medical University from Sep. 2008 to Oct. 2010. Expression of miR-34b gene and level of methylation in gene promoter were detected by real time PCR and methylation-specific PCR in the 2 kinds of tissues， respectively. Results The expression value of miR-34b mRNA in PTC tissues was 0.85±0.05， which was significantly lower than those of tumor adjacent tissues （1.62±0.09）， P=0.030. There were methylation in 18 （72%，18/25） PTC tissues， and 10 （40%，10/25） in tumor adjacent tissues， and the ratio of methylation was higher in PTC tissues （P=0.021）. In PTC tissues， methylation was not related to age， gender， tumor size， TNM stage， and invasion of the capsule （P＞0.05）， but was related to lymph node metastasis （P＜0.05）. Ratio of methylation in patients with lymph node metastasis was significantly higher than those of patients with no lymph node metastasis. Conclusion Methylation of miR-34b gene promoter is one of the reasons for inactivation of PTC， and it may be related to the development and metastasis of PTC， which needs to be further investigated.