The volatiles of two samples from Laobaigan base Baijiu fermented by “Laowuzeng” and “Sanpaijing” processes were respectively analyzed by headspace solid phase microextraction (HS-SPME) combined with comprehensive two-dimensional gas chromatography/time-of-flight mass spectrometry (GC×GC-TOF/MS). In the GC×GC-TOF/MS analysis, 234 and 253 volatiles were identified respectively, and a total of 273 volatiles were identified in the two kinds of base Baijiu samples, including 85 esters, 35 aldehydes,44 alcohols, 11 acids, 35 ketones, 5 phenols, 8 ethers, 9 furans, 11 acetals, 8 nitrogen-containing compounds, 11 sulfur-containing compounds, 3 lactones and 8 terpenes, among which the contents of ethyl lactate, ethyl acetate and ethyl decanoate were higher. The contents of aldehydes, phenols, nitrogen-containing compounds and sulfur-containing compounds in the base Baijiu of “Laowuzeng” process were 1.64,2.34,1.43 and 1.73 times of those in the base Baijiu of “Sanpaijing” process, which made the base Baijiu of “Laowuzeng” process had richer aroma including grass, malt, smoky, roasted and sulfur. However, the contents of esters, alcohols, furans, lactones and terpenes in the base Baijiu of “Sanpaijing” process were 1.30,1.27,1.31,1.65 and 1.57 times of those in the base Baijiu of “Laowuzeng” process, which made the base Baijiu of “Sanpaijing” process have stronger aroma of fruity, floral and sweet and the flavor was felt more elegant.