This study investigates the preparation, characterization, and property evaluation of Hericium erinaceus peptide–calcium chelate (HP-Ca). Hericium erinaceus, an edible mushroom rich in proteins and calcium-binding amino acids, was used as a source for peptides. The optimal conditions for hydrolyzing Hericium erinaceus peptides (HP) with high calcium-binding rate (CBR) were determined, followed by the optimization of HP-Ca preparation using the Box–Behnken design (BBD). The structure of the chelates was characterized, and their gastrointestinal stability and calcium absorption were evaluated. The optimal conditions for HP-Ca preparation were a pH of 8.5, temperature of 55°C, and a mass ratio of peptide/CaCl₂ of 4:1. Under these conditions, the chelates contained 6.79 ± 0.13% calcium. The morphology and energy-dispersive spectroscopy (EDS) analysis showed that HP-Ca was loose and porous, with an obvious calcium element signal. The ultraviolet–visible (UV) absorption and Fourier transform infrared spectroscopy (FT-IR) analysis indicated that calcium possibly chelates to HP via interaction with free -COO- from acidic amino acids and C = O from amide. HP-Ca displayed good stability against stimulated gastrointestinal digestion and significantly improved calcium absorption by Caco-2 epithelial cells. Thus, HP-Ca is a promising Ca supplement with high calcium bioavailability. The study provides a new idea for developing peptide-Ca supplements using edible fungi. The possible mechanism for high Ca absorption of the chelate should be investigated in the future.This study investigates the preparation, characterization, and property evaluation of Hericium erinaceus peptide–calcium chelate (HP-Ca). Hericium erinaceus, an edible mushroom rich in proteins and calcium-binding amino acids, was used as a source for peptides. The optimal conditions for hydrolyzing Hericium erinaceus peptides (HP) with high calcium-binding rate (CBR) were determined, followed by the optimization of HP-Ca preparation using the Box–Behnken design (BBD). The structure of the chelates was characterized, and their gastrointestinal stability and calcium absorption were evaluated. The optimal conditions for HP-Ca preparation were a pH of 8.5, temperature of 55°C, and a mass ratio of peptide/CaCl₂ of 4:1. Under these conditions, the chelates contained 6.79 ± 0.13% calcium. The morphology and energy-dispersive spectroscopy (EDS) analysis showed that HP-Ca was loose and porous, with an obvious calcium element signal. The ultraviolet–visible (UV) absorption and Fourier transform infrared spectroscopy (FT-IR) analysis indicated that calcium possibly chelates to HP via interaction with free -COO- from acidic amino acids and C = O from amide. HP-Ca displayed good stability against stimulated gastrointestinal digestion and significantly improved calcium absorption by Caco-2 epithelial cells. Thus, HP-Ca is a promising Ca supplement with high calcium bioavailability. The study provides a new idea for developing peptide-Ca supplements using edible fungi. The possible mechanism for high Ca absorption of the chelate should be investigated in the future.