Based on the physical model of ellipse reflecting cavity, the tangent-delay operation is proposed to change the evolution route of the systems , and a new class of discrete chaotic map systems is deduced based on the tangen t-delay operation. Simulation experiments show that the discrete chaotic systems have many special properties such as the maximum Lyapunov exponent is over zero , unchangeable equiprobability distribution and zero correlation in total field, there exists a square chaotic attractor when tangent delays one unit, and becom e ergodic state when tangent delays more units than one. The discrete chaotic sy stems can generate 2 independent pseudo-random sequences together. All of the pr operties suggest that the class of chaos systems possesses the potential applica tion in encryption.