The mass，momentum，energy transfer equations of a multi-component electromagnetic fluid were reviewed subject to viscous processes，heat transfer by conduction，radiation，and convection，electromagnetic energy transfer，matter diffusion and chemical reactions. These transfer equations were used to reestablish the entropy transfer equation for the electromagnetic fluid，and further to reconstitute the differential component equations for different forms of exergy and the differential equation for total exergy in the fluid by the definitions of thermal，pressure，chemical，kinetic，potential and electromagnetic forms of exergy. These component equations revealed the relations of transfer and inter-conversions between the different forms of exergy，including the breakdown into reversible and irreversible conversions，which provided an approach to comprehending the irreversible exergy transfer mechanism，to calculating correctly the exergy destruction due to reversibility，and to improving the efficiency and performance of electromagnetic fluid transfer process.