βketoacylCoA synthase (KCS) is the ratelimiting enzyme in the biosynthesis of very long chain fatty acids (VLCFAs). In this study, Lilium brownii var. viridulum Baker ‘Huangtianba’ was used as material, the CDS sequences of LbKCS5 and LbKCS17 genes were cloned by RTPCR using cDNA as a template, and sequence analysis, qRTPCR were performed to study their gene expression and stress induction analysis. The results showed that: (1) LbKCS5 and LbKCS17 contained 689 bp and 1 238 bp complete reading frames (ORFs), encoding 186 and 291 amino acids, respectively. Sequence similarity between LbKCS5 and oil palm KCS5，LbKCS17 and lotus KCS17 were 82.61% and 77.62%, respectively. (2) Expression level analysis indicated that both LbKCS5 and LbKCS17 were expressed in the vegetative organs of lily, with the highest expression in leaves and the least in roots. In floral organs, petals had the two genes’ lowest expression, the highest expression levels of LbKCS5 and LbKCS17 were in stamens and anthers, respectively. During the growth and development of flower buds, the two genes’ expression increased first and then decreased, reaching a peak at the yellow bud stage in petals; in leaves LbKCS5 reached the highest at the yellow bud, while the expression of LbKCS17 was generally low. (3) The transcriptional expression levels of these two genes surged under dehydration stress, and low temperature can induce LbKCS5 expression rinsing, but reduce the expression of LbKCS17; Our results show that LbKCS5 and LbKCS17 were expressed in different organs of lily and responded to dehydration and low temperature stresses, which provided a feasible approach and theoretical supporting for future studies on improving these two stresses tolerance and breeding of new varieties of lily.