The present study elucidated the advantages of using hydroxypropyl methylcellulose E5 (HPMC) as auxiliary excipient in maintaining storage stability and solubilization ability for curcumin amorphous solid dispersion (Cur ASDs) formulated by Eudragit E100 (E100). Polarized light microscopy and in vitro dissolution experiment was applied for confirming the ability of HPMC on inhibiting crystallization thereby maintaining storage stability in Cur ASDs. Meanwhile, as a non-ionic surfactant, HPMC can form micelles in pH 1.0 hydrochloric acid and played a role in solubilization ability on Cur. Critical micelle concentration (CMC), molar solubilization ratio (MSR) and micelle-water partition coefficient Kof surfactants (HPMC, E100/HPMC 1:1 and E100/HPMC 6:1) in pH 1.0 hydrochloric acid were calculated to determine the solubilization ability of surfactants. The results showed that the solubilization ability of E100/HPMC 6:1 was the best and the solubilization mechanism of E100/HPMC 6:1 was also different from HPMC and E100/HPMC 1:1.