Abstract: Applying comparative study on the characteristics of modular growth of five mutual species such as Stipa grandis, Leymus chinensis, Cleistogenes squorrosa, Lespedeza dahurica and Heteropappus altaicus, the grey-correlative analyses between the demographic growth analysis indexes and average temperature, precipitation and moisture had been carried out during months of the growth seasons from 1999 to 2000 in Research Stations of warm-temperate and moderate-temperate steppes of Inner Mongolia. The results demonstrated that the indexes of DRGR & DRGRa and DULAof these species were all higher in moderate-temperate steppe than warm-temperate steppe, showing the ecological characteristics of adaption themselves to the climate of shorter growth season and inadequate thermal condition,while longer duration of leaf area and modular quantity (DLAD & DMND) of these species reflected the adaption of the longer growth season and sufficient quantity of heat in warm-temperate steppe. Meanwhile, the greycorrelative degree between modular growth indexes of these species and moisture was remarkably higher in warm-temperate steppe than in moderate-temperate steppe, showing that modular growth of plant individual was more sensitive to the combination of water and heat in growth season in warm-temperate steppe,and indicating the response characteristics of plant modular growth in different thermal steppe region.