Abstract: The structure and spatial pattern of rodent communities were studied, sampled from July to September in the year 1979 in Baiyinxile typical steppe, Inner Mongolia. In this paper, the rodent species diversities were calculated based on the data from the same communities.There is positive correlation between the species diversities (H') of the plants and of the rodents in these communities. the evenness (J') of the rodent is correlated positively with plant evenness. There is no linear correlation between the species number of the plants and of the rodents.The rodent species diversity is correlated negatively with the height of the herb layer, the percentage of vegetation cover and the soil moisture content, respectively, The plant species diversity is also correlated negatively to these three parameters.H', the Shannon-wiener index, integrately respones to the evenness and the species number. Using H' for the species diversity of rodent community is better than the species number.