Human beings are experiencing serious desertification. Emphasis has been put on the importance of desertification early warning, both in the frameworks at intentional/national level to combat desertification, and in academic research. However, desertification early warning has not been generally carried out in practice. Based on the review of related researches, the following conclusions had been made. Firstly, traditional desertification assessment methods could not provide reliable scientific basis for early warning. Secondly, some Chinese researchers had built the frameworks of desertification early warning system. As these frameworks were impracticable, traditional evaluation methods were still applied in case studies. Thirdly, many efforts had been made on the identification of early warning signals in foreign studies. Early studies were generally based on the surveys of vegetation and soil survey. As the development of regime shifts theory, recent studies began to focus on the time series research and patch distribution. Further studies could be carried out in the following areas. Firstly, to study the spatial variation of the ecosystem by time series research. Secondly, to take various feedback mechanisms and artificial pressure into early warning models. Thirdly, to improve the existed early warning frameworks by enhancing their operability.