Abstract: To further optimize the structure of the greenhouse，the variation characteristics of the temperature in south edge area in the sinking-mode greenhouse of the sinking depth 80 cm was analyzed and the comparison of the soil temperature of this mode and the non-sunken greenhouse was made. The temperature inside greenhouse 0～5m from south vertical wall (0.1m depth) and outside greenhouse 0～1m from south vertical wall (0～60cm depth) were measured. The results showed that the distance of boundary point for soil temperature at the south edge area was 160 cm from the south vertical wall of the greenhouse in January, and it was only 20cm from that in late March．In mid-January, in one day the farthest point appeared during ≥03:00～09:00, which was located at 180cm from the south, and the nearest point appeared during ≥15:00～18:00, which was located at 60 cm. Compared with the south edge area in the non-sunken greenhouse, the size of the sinking greenhouse was obviously reduced. At distance 0～1m from south vertical wall (0～60cm depth) outside greenhouse, relatively stable interface of temperature existed in both the facade that perpendicular to south vertical wall and the facade that perpendicular to surface. As one of an index of the optimized design of a greenhouse, the reduction of edge area can show the superiority of the sinking-mode sunlight greenhouse in Henan province.