This study investigates the preparation, characterization, and property evaluation of Hericium erinaceus peptide–calcium chelate (HP-Ca). The authors aimed to optimize the hydrolyzing conditions for high calcium-binding rate (CBR) peptides and to evaluate the gastrointestinal stability and calcium absorption of the resulting chelates. The optimal conditions for peptide hydrolysis were determined using papain with a hydrolysis time of 2 hours. The Box–Behnken design (BBD) was used to optimize the preparation conditions of HP-Ca, and the CBR was found to be maximized at a peptide/CaCl2 ratio of 2:1, a temperature of 40°C, and a pH of 8. Characterization techniques, including SEM, EDS, UV absorption, FT-IR, XRD, and thermogravimetric analysis, confirmed the successful chelation of calcium by the peptides. The HP-Ca showed improved thermal stability and good gastrointestinal stability, with minimal calcium loss during simulated digestion. In vitro experiments demonstrated that HP-Ca effectively facilitated calcium absorption in Caco-2 cells, indicating its potential as a high-bioavailability calcium supplement. The study provides a novel approach to developing peptide-Ca supplements using edible fungi and highlights the importance of further investigating the underlying mechanisms of high calcium absorption by HP-Ca.This study investigates the preparation, characterization, and property evaluation of Hericium erinaceus peptide–calcium chelate (HP-Ca). The authors aimed to optimize the hydrolyzing conditions for high calcium-binding rate (CBR) peptides and to evaluate the gastrointestinal stability and calcium absorption of the resulting chelates. The optimal conditions for peptide hydrolysis were determined using papain with a hydrolysis time of 2 hours. The Box–Behnken design (BBD) was used to optimize the preparation conditions of HP-Ca, and the CBR was found to be maximized at a peptide/CaCl2 ratio of 2:1, a temperature of 40°C, and a pH of 8. Characterization techniques, including SEM, EDS, UV absorption, FT-IR, XRD, and thermogravimetric analysis, confirmed the successful chelation of calcium by the peptides. The HP-Ca showed improved thermal stability and good gastrointestinal stability, with minimal calcium loss during simulated digestion. In vitro experiments demonstrated that HP-Ca effectively facilitated calcium absorption in Caco-2 cells, indicating its potential as a high-bioavailability calcium supplement. The study provides a novel approach to developing peptide-Ca supplements using edible fungi and highlights the importance of further investigating the underlying mechanisms of high calcium absorption by HP-Ca.