Mycelium is the vegetative part of a fungus or most microorganisms, consisting of a mass of branching, thread-like hyphae. It is through the hyphae that a fungus absorbs nutrients from its environment. For most fungi, the ability of nutrition translation from mycelium to fruit body is determined by growth status of hyphae. It is very necessary to study the effect of environmental factors on mycelium growth, and know the befitting environment condition. However, finding a good data acquisition method for measuring the mycelium is the key point.A new method was introduced in the paper. The method is using image identification and space data analysis function of the GIS to acquire development rate of mycelium i.e. hyphae. Pleurotus eryngii under commercial production is taken as example. The effect of different temperature and humidity on mycelium growth was analyzed. It is hoped to explore a new method for scientific and precise measurement the growth status and development rate of mycelium.