Objective　To investigate  clinical features of  Peutz-Jeghers syndrome (PJS) and genetic change in STK11. Methods　Clinical data and genetic change in STK11 gene of four PJS children were retrospectively analyzed. Results　Four patients have hyperpigmentation on their lips, buccal mucosa or fingers. Intestinal polyposis was found at different locations of gastrointestinal tract. Polypectomy was performed in four patients and pathological section displayed the muscle fibers of the muscularis mucosae form a dendritic structure. And we found 4 heterozygous mutations (c.582C>A，c.580G>A，c.719C>G and c.879insA) on STK11 gene  in these patients. Conclusions　The PJS patients have typical clinical features; gene detection is helpful to early diagnosis, and we found a novel mutation (c.879insA)  in STK11 gene.