Scale insects (Hemiptera: Coccoidea) compose a group of important plant pests of agricultural crops, forest plants, ornamental plants and fruit trees. The history of the study of entomopathogenic fungi as a biological insecticide is reviewed according to the three developmental stages: the pioneering stage, the slow development stage, and the prosperity stage. Additionally, the status of this field in China was discussed. A list including approximately 140 species within 55 genera of the recorded fungal pathogens of scale insects in the world was provided. Finally, we provide four suggestions for the development of entomopathogenic fungi in the future.