Microarray has been used as a tool in molecular biology research for many species. Many different types of microarray are available, however, DNA microarray is the most popular array that is being used in many studies. With the ability to observe many genes' expression, DNA microarray has been used to evaluate transcriptomic variations. Through the advance of other technologies such as next-generation sequencing and bioinformatics, microarray can be coupled with other tools to improve capability of transcriptome profiling and analysis. This review discusses the principle of microarray, its main direction in plant research and related researches in forest tree physiology.