In this paper, cracking behavior of distributed microcracks is discussed using a numerical simulation. The microcracks are initially distributed in a rectangle region. The directions and locations of the cracks are chosen at random. Three kinds of length distributions are used, such as a uniform length, a random length distribution and a fractal length distribution. The crack propagations from the initially distributed cracks are analyzed under a uniaxial tensile load using liner elastic fracture mechanics. The global behaviors of various crack distribution are studied. Results obtained from the numerical calculations indicate that the effect of the crack length distribution is minor in term of the macroscopic behavior of the cracked body.