We have investigated the morphology developed in the ordering process for a nearly symmetric polystyrene-bloch-polyisoprene diblock copolymer when the copolymer is rapidly brought from a disordered state to an ordered state. The ordering process was explored as a function of time and temperature primarily by transmission electron microscopy(TEM) : the microdomain structures formed during the ordering process were observed on specimens frozen at particular times in the ordering process. Complementary small-angle X-ray scattering experiments on the specimens before and after freezing assured that the structures existed before freezing were really conserved in the frozen specimens. The TEM observations showed that the ordered grains of the lamellar microdomain were developed in the matrix of the disordered phase and that the grains grew at the expense of the disordered phase at all the temperatures covered in this study. The coexistence of the ordered and disordered phases suggests that this ordering is a nucleation and growth process. We found that the shape of the lamellar grains developed in the disordered phase were very anisotropic at all stages and temperatures covered in this study : the size along the lamellar normals was much larger than that parallel to the lamellar interfaces. Furthermore in the early stage of the ordering, the lamellae formed in the ordered grains were perforated but they eventually become solid lamellae.