The polylactic-co-glycolic acid polyethylene glycol conjugated with cell penetrating peptide R (PLGA-PEG-R)/polysulfadimethoxine-folate nanoparticles loaded with docetaxel (DTX) and GDC0941 (R/PSD-Fol NPs) were prepared to overcome multidrug resistance (MDR) and enhance the antitumor activity. First, polysulfadimethoxine-folate was synthesized to construct the R/PSD-Fol NPs. The R/PSD-Fol NPs were prepared with the abilities of effective entrapment and drug loading. Due to the pH-sensitive effect of PSD-folate, the releasing of DTX and GDC0941 from the R/PSD-Fol NPs was lower in pH 7.4 buffer solution than that in pH 5.0 buffer solution. The half maximal inhibitory concentration (IC) of MCF-7 and resistant to doxorubicin (MCF-7/Adr) cells illustrated the cytotoxicity of R/PSD-Fol nanoparticles by using the MTT method. The uptake of R/PSD-Fol NPs was visualized by using the fluorescence of Rh-123 to detect the targeting effect of folate on the surface of R/PSD-Fol NPs. The results of the cell apoptosis and the depolarization of mitochondrial membrane potential (MMP) were adopted to show the cytotoxicity of the R/PSD-Fol NPs on MCF-7/Adr cells. The Western blot revealed the inhibition of PI3K/Akt pathway in MCF-7/Adr cells induced by R/PSD-Fol NPs. Finally, both in vivo distribution and in vivo antitumor showed the R/PSD-Fol NPs displayed the better distribution at tumor site and the stronger suppression of tumor growth in the tumor bearing nude mice compared with control group. It was concluded that R/PSD-Fol NPs loaded with DTX and GDC0941 could overcome MDR and enhance the antitumor effect further.