With four Pleurotus eryng# varieties as test materials, the mycelium pelletdensity, dry weight and diameter, fermentation broth pH value, and deoxidized sugar content were determined during their liquid fermentation to investigate the growth of mycelia and changes in fermentation broth. In addition, the sensory, biochemical and microbiological indicators of excellent P. eryngii mycelia were determined by sensory tests, microscope morphology observation and mycelium pellet back-inoculation tests. The results showed that the standards for high-quality liquid spawn of P. eryngii were as follows： bacterial liquid was light yellow and clarifiedwith rich bitter almond flavor but no bacterial contamination; mycelium pellets were visible, white and uniform with burrs on the surface, diameter 〈2.5 mm and concentration of 80%-100%; mycelium pellets were stout, and there were 3--4 clamp connectionsper visual field under the microscope; fermentation time was generally 120-144 h.
