With the versatility of structural performance in magnesium alloys, their Achilles hill remains to be corrosion property. Mg community agrees that traditional methods are insufficient for revealing the root cause of difficulties in controlling Mg degradation rate. Therefore, developing new methods allowing simultaneous assessment of several characteristics is of great importance now. We designed an advanced cell for immersion testing allowing simultaneous assessment of three complementary characteristics of Mg corrosion in aqueous environments: isothermal calorimetry, pressure and pH levels. Isothermal calorimetry monitors in-situ heat production rate during chemical reactions, which can be recalculated to corrosion rate if the enthalpy of a process is known. As the formation of MgO/Mg(OH)2 depends on a solution pH, its measurement makes it possible to select the correct enthalpy. Pressure monitoring allows alternative quantification of corrosion rate through hydrogen production. The proof-of-concept testing to be presented reveals details of corrosion process depending on NaCl concentration.