Background: There are growing number of researches have shown that mesoderm posterior basic helix-loop helix (BHLH) transcription factor 1 (MESP1) plays a crucial role in the development of tumors. However, its expression pattern and function in non-small cell lung cancer (NSCLC) are still unknown. Methods: MESP1 expression and biological process were investigated in NSCLC based on bioinformatics analysis. The mRNA or protein expression levels of MESPI were measured by quantitative real-time PCR (qRT-PCR) and western blot (WE) assay in NSCLC cells and clinical tissue samples. Then, we used small interfering RNA (siRNA) interference to knocking down expression of gene in NSCLC cells. Cell proliferation was performed using cell counting kit-8 (CCK-8), colon forming assay and real-time cell analyzer (RTCA); transwell chambers and RTCA were used to analysis cell migration and invasion. Besides, analyses of the cell cycle progression and apoptosis were measured via BD JAZZ flow cytometric analysis. All the experiments were repeated >= 3 times. And analyses were performed using SASS software version 21.0 and GraphPad Prism 6.0. P<0.05 was considered statistically significant. Results: Detection of MESP1 showed that mRNA was up-regulated in NSCLC cells and patients compared with the normal controls (P<0.05). And high expression of MESP1 were correlated with increasingly cell proliferation, metastasis, cycle and apoptosis. Besides, through WB experiments, it was found that knocking down MESP1 mainly activated the caspase-3/PARP1 signal pathway. Furthermore, it was also verified from clinical samples that MESP1 was highly expressed on both mRNA and protein aspect. Conclusions: Our study suggested that MESPI is indeed highly expressed in NSCLC, and MESP1 high expression obviously promote cell proliferation, migration, invasion. What's more, it has good sensitivity to the occurrence and development of NSCLC patients. This can be used as a novel potential therapeutic target for NSCLC.