In the present study, two samples (abaxial leaves with and without penniform fiber)’s cDNA were sequenced based on Illumina HiSeq2500 to analyze the fiber development mechanism. The results indicated that 108 694 unigenes were obtained. Then, 1 605 differential expressed genes (DEGs) were selected. 830 DEGs were divided into 39 GO terms, 512 DEGs were assigned to 25 categories with COG database. Function annotation against KEGG database obtained 315 DEGs. 10 significantly reliable enrichment pathways were selected by enrichment analysis of 79 KEGG pathways. DEGs in “amino sugar and nucleotide sugar metabolism” which control cellulose biosynthesis, DEGs in “phenylpropanoid biosynthesis” which control lignin biosynthesis and DEGs in “plant hormone signal transduction” which control auxins signal transduction were downregulated. While those in “plant hormone signal transduction” which control cytokinin and abscisic acid signal transduction were upregulated. These results greatly enriched genetic information of G. delavayi and provided basic data for function verification and genetic improvement of fiber traits in the future.