Habotai silk was hydrolysis-aged by HCl and NaOH to study the change of its crystallinity, orientation, tensile mechanical properties, weight loss rate etc. The results show that the hydrolysis-aging degree of silk by HCl was slight, but that by NaOH was significant. Both the crystallinity and orientation were reduced significantly by NaOH but slightly by HCl. The weight loss rate of silk samples rose like the parabola with the increase of alkali concentration, and it rose linearly against time. The breaking strength of silk fibers was affected significantly by the alkali hydrolysis aging, particularly in the initial stage and its weight loss rose linearly with the increase of alkali concentration. The PH values of the hydrolysis solution both by HCl and NaOH were close to neutral.