The king oyster mushroom, Pleurotus eryngii (DC.:Fr.)Quél., would have a great market potentiality in the coming years. It has been valued as the best one of all Pleurotus species due to its excellent consistency of cap and stem, and pleasant aroma as well as culinary qualities. The conduction of king oyster mushroom research project was started in 1991 at Agricultural Research Institute. The project was financially supported by the Council of Agriculture, Executive Yuan, Republic of China. After carrying out a series of experiment and study, technology for the automatic bottle cultivation system of this mushroom including sawdust sieving, substrate mixing, filling, holing, capping, autoclaving, cooling, automatic mechanical inoculation, spawn running, surface holing, stimulating for fruiting body, harvesting, waste scratching and the bottles can reuse for the mushroom cultivation. In the meanwhile, four new cultivars of the mushroom (B011, B012, B030 and B112) were developed as well by breeding for commercial production in Taiwan.