In order to explore the structural characteristics and digestion stability of pectin calcium formed by pectin with different degrees of esterification (DE)， this article used five different pectin with different DE to react with calcium chloride to obtain five different pectin calcium with different DE. And its yield， calcium content， infrared， X-ray diffraction (XRD)， electron microscopy(SEM) et al.， structural features and its stability in vitro simulated digestion were compared. Results showed that the yield of pectin calcium was 50%-87%. Pectin calcium formed by the reaction of pectin with DE=10% and Ca2+ (DE10-CaP) had the highest calcium content (88 mg/g). DE59-CaP had the lowest calcium content (43.6 mg/g). The binding form of Ca2+ in calcium pectinate and carboxylate was single monodentate coordination binding type， with three binding regions intermolecular and intramolecular， which further improved the binding mode of pectin calcium. XRD showed that low-ester pectin calcium had a 2θ=21.5° diffraction peak more than that of high-ester pectin calcium. SEM showed that the apparent structure of low-ester pectin calcium was more compact and massive， and high-ester pectin calcium was in the form of flakes. It can be obtained by the in vitro simulated gastrointestinal digestion test that the calcium release rate of high-ester pectin calcium was higher. This research is helpful for in-depth understanding of the microstructure and application properties of pectin calcium.