Based on metamaterial theory, a terahertz metamaterials with analog of electromagnetically induced transparency (EIT) effect is designed. The cell unit are consisted of three metal wires and polyimide substrates. Through the radiation of the terahertz wave, the bright-dark mode is excited directly and indirectly to form the EIT resonance, and the phase interference is formed through the superposition of the resonant spectrum between the elements to make the metamaterial transparent to the incident terahertz wave. The formation of transparent window has great value in the application of loss detection. In this paper, the influence of the loss of the measured material on the transmission peak is studied based on the change of the peak of transmission peak. The result shows that there is a close nonlinear relationship between the loss tangent angle of the measured material and the penetration rate of the metamaterial, which provided ideas and foundations in the measurement of the loss detection.