The rare edible and medicinal fungus Antrodia cinnamomea has a substantial potential for development. In this study, Illumina HiSeq 2000 was used to sequence its transcriptome.The results were assembled de novo, and 66,589 unigenes with an N50 of 4413 bp were obtained. Compared with public databases, 6,061, 3,257, and 2,807 unigenes were annotated to the Non-Redundant, Gene Ontology, and Kyoto Encyclopedia of Genes and Genomes databases, respectively. The genes related to terpene biosynthesis in the mycelia of A. cinnamomea were analyzed, and acetyl CoA synthase (ACS2 and ACS4), hydroxymethylglutaryl CoA reductase (HMGR), farnesyl transferase (FTase), and squalene synthase (SQS) were found to be upregulated in XZJ (twig of C. camphora) and NZJ (twig of C. kanehirae). Moreover, ACS5 and 2,3-oxidized squalene cyclase ( OCS) were highly expressed in NZJ, while heme IX farnesyl transferase (IX-FIT) and ACS3 were significantly expressed in XZJ. The differential expression of ACS1, ACS2, HMGR, IX-FIT, SQS, and OCS was confirmed by real-time quantitative reverse transcription PCR. This study provides a new concept for the additional exploration of the molecular regulatory mechanism of terpenoid biosynthesis and data for the biotechnology of terpenoid production.