Abstract: In order to investigate and solve the reality that sesame seeds were rich in calcium, but rarely used as calcium supplement food. In this study, two kinds of black and white sesame seeds were used as raw materials, which were processed in four ways: Steaming, microwave, baking and ultra-high pressure (UHP). Afterwards, the basic components were analyzed, the release rate of calcium ions from sesame seeds was determined using in vitro simulated digestion, and a mouse model of phytic acid inhibition of calcium absorption was constructed to evaluate the effects of different processing methods on the calcium bioavailability of sesame seeds. The results showed that steaming processing and roasting at 180 ℃ resulted in a significant decrease (P<0.05) in phytic acid content of black and white sesame seeds, microwave processing resulted in a decrease but not significant (P>0.05) in phytic acid content of black and white sesame seeds, and UHP processing resulted in a significant increase (P<0.05) in phytic acid content of black and white sesame seeds. All processing methods increased the ash content as well as the protein content of sesame seeds. Steaming for 50 min resulted in a significant increase in calcium release from black sesame seeds (P<0.001), microwave processing did not have a significant effect on calcium release from sesame seeds (P>0.05), baking at 120 ℃ also resulted in a significant increase in calcium release from white sesame seeds (P<0.001), and UHP processing resulted in a significant increase in calcium release from both black and white sesame seeds (P<0.001). Animal experiments showed that the serum alkaline phosphatase (ALP) level of mice in the group with processed black sesame feed was significantly lower than that of mice in the group with unprocessed black sesame feed (P<0.05), and that microwave, baked, and UHP processed sesame feed had a significant calcium-supplementation effect on mice, with a significant increase in bone calcium content (P<0.001). In summary, UHP processing significantly increased the release rate of calcium ions from sesame seeds and showed the best results in animal experiments, most favorable to improve the bioavailability of calcium in sesame seeds in vivo, followed by microwave processing as well as baking processing.