：The effective second-order nonlinearity and terahertz emission properties of DAST crystal are mainly studied. Based on the metastable region of DAST-methanol solution, the growth experiment of DAST is carried out by solution cooling methods. It is found that the higher the cooling rate, the faster the crystal growth rate, but the polycrystalline is easy to occur. In the later stage of crystal growth, the lower cooling rate is beneficial to the increase of crystal thickness. After grinding, the surface roughness of the polished crystal could meet the optical test level(micron level) requirement. The average effective second order non-linear coefficient of DAST chip is 16.58 pm/V. Terahertz emission in the frequency range of 0.84-10 THz is realized, and the maximum emission intensity is at 2.72 THz.