The influence of various factors on the dynamics of the Lang-Kobayash equations with nonlinear gain saturation coefficient was investigated. Because of the existence of time delay feedback, there may exist different ECM solutions, which may lose the stabilities via Hopf bifurcation and further evolve to various forms of chaos. The interactions between different attractors may cause the catastrophe of chaotic structures, which results in sudden space scale change of chaos. With the change of time delay, these modes will appear again and again. It is worth to point out that, for certain parameter conditions, two ECM solutions with different frequencies may coexist, one of which may lose the stability via Hopf bifurcation and leads to chaos by cascading of perioddoubling bifurcations, while it may finally settle down to the other ECM solution via chaos crisis. Furthermore, with the variation of nonlinear gain saturation coefficient, the two frequencies of the quasiperiodic movement in polar coordinate are quite separated, which results in the obvious fastslow effect in the lasers.