The basic properties of the minimal imaginary roots of the hyperbolic Kac-Moody algebra were studied. According to the character of the Dynkin diagram of the generalized Cartan matrix corresponding to the hyperbolic Kac-Moody algebra, all the minimal imaginary roots of the n-order hyperbolic type Kac-Moody algebra were listed, where $5 \leqslant n \leqslant 10$.