Novel biocompatible and biodegradable pH/reduction dual-responsive oxidized alginate-doxorubicin mPEG-OAL-DOX/Cys) prodrug nanohydrogels were designed for tumor-specific intracellular triggered release of anticancer drug DOX by conjugating DOX via acid-labile Schiff base linkage into the PEGylated oxidized alginate (mPEG-OAL) cross-linked with bioreducible disulfide bond. The effect of the complexation with cyclodextrins (alpha-CD and beta-CD) before or after the cross-linking of the mPEG-OAL on the DOX content and controlled release performance was investigated. It was found that the cyclodextrin inclusion complex prodrug nanohydrogels mPEG(CD)-OAL-DOX/Cys, prepared by cross-linking of the mPEG-OAL after complexation with cyclodextrins, exhibited better pH/reduction dual-responsive controlled release performance than the mPEG-OAL-DOX/Cys(CD) ones prepared by cross-linking of the mPEG-OAL before complexation with cyclodextrins, owing to the supramolecular cross-linking of the adjacent pseudopolyrotaxanes. Especially for the cyclodextrin inclusion complex prodrug nanohydrogels mPEG(alpha-CD)-OAL-DOX/Cys, DOX was released rapidly under lower pH media mimicking the tumor microenvironment and completely released within 48 h, while the premature leakage under the simulated physiological condition was similar to 40%, without burst release in both cases. The cellular toxicity and uptake results demonstrated that the mPEG(alpha-CD)-OAL-DOX/Cys prodrug nanohydrogels possessed similar inhibition against cancer cell growth in comparison with the free DOX and enhanced drug intracellular accumulation.