The development of functional materials for efficient protein removal and antipsychotic drug extraction in biological samples is attracting great interest. In this study, a nanoscale ethylenediamine-functionalized chromium-based metal–organic framework (MOF) (MIL-101-ED) was designed, synthesized, and applied for the one-step removal of proteins and the extraction of antipsychotic drugs in serum samples. The introduction of ethylenediamine in the MIL-101 nanoparticle (NP), in which amino and carbon chains can enhance the hydrogen-bond interaction and π–π interaction between functionalized MOFs and antipsychotic drugs, i.e., risperidone, etc. The antipsychotic drugs were ionized and amino groups were protonated at pH = 3, due to electrostatic interaction, and the negatively charged drugs were adsorbed on the surface or even entered the pores of MOFs. The adsorption efficiencies of the six kinds of drugs ranged from 80.1 to 101.4%. Owing to the exclusion action, proteins were excluded from MIL-101-ED and the exclusion rate ranged from 91.9 to 94.0%. Furthermore, MIL-101-ED can be easily regenerated and reused four times without a significant reduction in the protein exclusion rate and adsorption capacity. Coupled with high-performance liquid chromatography–diode array detection (HPLC–DAD) strategy, the application of MIL-101-ED for extracting the antipsychotic drugs and their metabolites in serum samples was developed. The recoveries of antipsychotic drugs and their metabolites in serum ranged from 83.2 to 110.8%, and the related detection limits were all <5.55 ng mL–1. Compared to the traditional extraction methods, the pretreatment steps of MIL-101-ED have the advantages of easy operation and reducing the environmental pollution. Here, we propose that MIL-101-ED, as a kind of restricted access media nanophase material, can be applied to extract antipsychotic drugs in serum samples.