The preparation of co-amorphous drug systems by adding a small molecular excipient is a promising formulation in the modern pharmaceutical industry to improve the solubility, dissolution rate, and bioavailability of poorly soluble drugs. In this study, palbociclib co-amorphous systems with organic acids (succinic, tartaric, citric, and malic acid) at molar ratios of 1 : 1 were prepared by co-milling and characterized by differential scanning calorimetry (DSC), fourier transform infrared spectroscopy (FTIR) and solid-state nuclear magnetic resonance (SS-NMR). These solid-state investigations have confirmed the formation of co-amorphous salts between PAL and organic acids. The solubility, dissolution rate and stability of the four co-amorphous drug systems were significantly improved compared with these of crystalline and amorphous palbociclib. The biosafety of the co-amorphous drug systems was the same as that of palbociclib without affecting the efficacy of the drug and eliciting toxic side effects. These comprehensive approaches for the palbociclib–acid co-amorphous drug systems provided a theoretical basis for its clinical applications.