Abstract: The meat samples of Scylla paramamosain were treated by graphite microwave digestion. ICP-MS was used to determine Ca²⁺ and Mg²⁺ simultaneously. The correlation coefficient of standard curve was ≥ 0.995. The pretreatment time was short and the digestion effect was good. The results showed that the average contents of Ca²⁺ and Mg²⁺ in S. paramamosain were 471 and 2 508 mg/kg in hard shell stage, 385 and 1 565 mg/kg in molting stage respectively. there had no significant differences in Mg²⁺, and had significant difference in Ca²⁺ concentration before and after molting stage. In order to make the Scylla molt and harden smoothly during the growth of the crab, it was suggested that Ca²⁺, Mg²⁺ should be supplemented reasonably in the culture pond.

Key words: Scylla paramamosain, Ca²⁺, Mg²⁺, ICP-MS