Quercus mongolica Fisch is a native species at the temperate zone of East Asia， and is highly valuable considering its application and economic potential. Trihelix transcription factors are related to plant light response， growth and development， and abiotic stress. In order to study the performance of Trihelix transcription factors in Quercus mongolica under different shading and water stress， 34 QmTHs （designated QmTH01 to QmTH34） were identified from the genome of Quercus mongolica by bioinformatics analysis. By clustering analysis with 29 Trihelix transcription factors identified in Arabidopsis thaliana， the Trihelix transcription factors can be divided into five subgroups including GT-1， GT-2， GT-γ， SH4 and SIP1. QmTHs were found on 10 chromosomes of Quercus mongolica， encoding for the putative proteins ranged from 189 to 897 aa， with isoelectric points ranging from 4.58 to 9.78. A total of 14 different cis-acting elements were identified in the promoters of QmTHs， in which the elements related to methyl jasmonate response， abscisic acid response and light response were often found. According to gene expression analysis under different shading and water stress， the transcripts of QmTH01， QmTH14， QmTH22， QmTH24 and QmTH33 were relatively high under high light intensity， and significantly down-regulated with the decrease of light intensity， indicating that these five genes were involved in the growth physiology of Quercus mongolica under high light response. The expressions of QmTH06， QmTH17 and QmTH24 were significantly up-regulated under watering treatments （April， May， June， July and August； once per month）， indicating that these genes possibly mediated the response of Quercus mongolica to water stress.