A study of the relationship between the vasculature and cell poliferation characteristics give some insight into the mecanism of the tumor growth. So the author observed the corrosion casts of tumor microcirculation by scanning electron microscope and explored the mechanism by which tumor tissue develops. Then the facts mentioned below were clarified. 1) Tumor vessel growth was divided into 4 stage according to the chin vascular morophology: (1) slight capillary alteration; (2) formation of fine capillary netwark; (3) modification in arteries; (4) ncrosis. 2) To quantify these vascular changes, the auther measured vascular volum, diameters of the vessels, vascular surface area, length and numberof buds by about 400 sheet of photographs which obteined by SEM. In the tumor tissue the values changes characteristcally in each stage. From the first to second stage, neovascularization was high in the tumor. In the third and forth stage, these values decreasd rapidly. 3) The auther observed vascular regeneration and rev ealed that host vessel give rise to buds which grow in length and width to form sprouts meet, they fuse, giving rise to loops or crossconnection and ultimately to intricate netwarks.