Abstract: 【Objective】 To study the nutritional quality and optimal harvest time of wild Qinghai Mandragora caulescens in different tissues and different growth periods.【Method】 Using wild Qinghai M. caulescens as a test material,12 indexes such as water content,soluble protein,soluble sugar,total phenolics,and flavonoids in its three tissues（leaves,fruits at various stages of ripeness,and roots） were detected by spectrophotometer,microplate reader,and high performance liquid chromatography.【Result】 The nutritional quality content of different tissues of Qinghai M. caulescens varies widely,and sucrose is the main component of the soluble sugar of Qinghai M. caulescens. Among them,the soluble protein content of fresh leaves was the highest,and the total phenol content of old leaves was the highest,and there were significant differences with other tissues（P＜0. 05）. The content of starch,reducing sugar and flavonoids in fruit IV is the highest. The growth index from fruit I to IV first increased and then decreased,and the content of soluble protein and soluble sugar was the highest in fruit III. Soluble sugars were significantly positively correlated with sucrose,reducing sugars,and starch. Sucrose was significantly positively correlated with reducing sugars and starch,and very significantly positively correlated with free amino acids. Total phenolics were negatively correlated with free amino acids,soluble sugars,sucrose,and starch,and flavonoids were negatively correlated with soluble proteins and free amino acids.【Conclusion】 The suitable harvest period of wild Qinghai M. caulescens is fruit ripeness III.