Stability is a basic topic in ecology. As an important component of global ecosystem function, soil ecosystems play an essential role in elemental cycling. Soil ecosystem stability is defined as the inherent ability of a soil ecosystem to resist change and to recover after disturbance. Similar to the studies on macro-ecosystem stability, soil ecosystem stability can be measured using resistance and resilience indexes. Studies in the past decade show that the results of soil ecosystem stability depend largely on the particular soil process and disturbance applied. Commonly used disturbances in experiment trials included heat, Cu and Hg stress, salt stress, and drying-rewetting cycling. Frequently measured microbial processes included basal soil respiration, nitrification, mineralization and bacterial growth rate. Among the factors that can be measured, microbial diversity-stability relationships remain the best surrogate of soil ecosystem stability. Techniques for obtaining soil diversity gradients were developed. Results showed a remarkable ability of soil ecosystems to maintain essential functions under stress that reduced soil microbial diversity significantly. In this paper critical issues in soil ecosystem stability are defined and discussed.