The single crystal of tetraamminediazido cobalt(Ⅲ) perchlorate(DACP) was prepared，and its crystal structure was determined by a X-ray single crystal diffractometer. The results show that the crystal is triclinic belonging to space group of P-1 with crystal parameters of the unit cell dimensions: a =0.74229(9)nm，α =93.244(2)°； b=1.2127314) nm，β =100.074(2)°； c=1.8124(2)nm，γ =98.033(2)°, volume V=1.5851(3) nm³, Z =6,calculated density D_c=1.952 mg·mm-3,absorption coefficient μ=1.901 mm^-1, F(000)=948. The compound is very sensitive to laser with a wavelength of 635 nm.