Abstract: Recently, terahertz science and technology has developed rapidly, showing potential applications in security and anti-terrorism involving drugs, explosives, hazardous articles, and so on.Among all the techniques, free space terahertz time domain spectroscopy exhibits excellent potential,but certain critical problems need to be solved, such as terahertz spot size and sample volume. Fortunately,the appearance of subwavelength artificial structures including metamaterials and surface plasmon devices offer new possibilities. This paper reviews our research work on terahertz subwavelength artificial structures for sensing applications, including thin film, gasoline and isotope sensing.It is shown that our devices have excellent sensitivity. Finally, we discuss the prospects and challenges of this technique.