The present study focuses on modeling and analyzing the MHD mixed convection flow in a double-cooled lithium-lead (DCLL) blanket of a fusion reactor using finite element simulation. Special attention is given to the effects of the Hartmann number and Grashof number on the flow and heat transfer conditions in MHD mixed convection. It is observed that the Hartmann number and Grashof number are the primary parameters influencing the flow and temperature fields of MHD mixed convection, representing the intensity of the MHD effect and the intensity of the mixed convection, respectively. The combined effects of the Hartmann number, Grashof number, and conductivity of the runner inserts on the MHD flow are comprehensively analyzed. Moreover, several dimensionless numbers are introduced to evaluate the heat transfer characteristics of the MHD mixed convection flow in the MHD blanket runners.