Abstract: Sourdough is used in the production of fermented cooked wheaten food, producing unique flavors and improving the quality and nutrition of the product. In this study, the sourdough of two kinds of fruits was prepared with red grape and pear as the main culture medium, and the changes of pH, total titratable acid (TTA), free sulfhydryl content and protein secondary structure of the dough by two kinds of sourdough were studied, as well as the effects on the microstructure, edible quality and nutritional properties of porous dried noodles. The results showed that the fermentation dough made with sourdough addition had lower pH value, higher TTA and free sulfhydryl content; Fourier transform infrared spectroscopy result showed that the content of β-sheet and random curling decreased, while the content of α-helix and β-turn increased and the flexibility of the protein chain enhanced; Compared with unfermented dried noodles, sourdough fermented porous dried noodles had loose interior, increased thickness, and uneven holes in size. The swelling index, water absorption, and fracture resistance were all improved to some extent; In terms of nutrition, the total phenol content of porous dried noodles fermented by sourdough was significantly increased, the amino acid composition pattern was optimized, and the concentrations of phytic acid and tannin, two common anti-nutritional factors in cereals, were greatly reduced. The research can provide a theoretical basis for the application of spontaneous sourdough in fermented dried noodles.