In the study， 7 strains of Lactobacillus delbrueckii subsp. bulgaricus isolated from traditional fermented dairy products are used to determine the changes of pH， titratable acidity， viable counts and viscosity during the production and storage （12 h） of fermented milk. In addition we detected for the flavor substances produced during storage （12 h） of fermented milk by solid phase microextraction combined with gas chromatography-mass spectrometry（SPME-GC-MS） methods. The results indicate that the IMAU62115 displayed the shortest fermentation time of 7.0 h and the number of viable cell counts of fermented milk gave the highest value of 4.95×108 CFU/mL， the TA reached 95 °T and the viscosity was 820 mPa·s. Among the 7 strains storage for 12 h， the flavor components of these strains in fermented milk had a significant difference and 29， 28， 26， 26， 32， 31 and 26 kinds of flavor substances were detected in IMAU20403， IMAU20396， IMAU62121， IMAU62115，IMAU20220， IMAU20227 and IMAU20234 respectively， mainly including acids， aldehydes， ketones， alcohols and esters， etc. Among them， the main characteristic flavor substances in IMAU62115 fermented milk are diacetyl， acetoin， 3-methylbutyraldehyde， 2-nonanone and so on. It has a high concentration of these flavor compounds in fermented milk， and the OAV value is greater than 1. Thus it has a great contribution to the flavor of the fermented milk. Therefore， the strain of Lactobacillus delbrueckii subsp. bulgaricus IMAU62115 screened in this study is a strain with excellent fermentation characteristics.