Abstract: For convenient maintenance, bolt connection and impaction by locking mechanism are usually used between solid state module and cold plate instead of jointing connection in electronic equipments. The thermal contact resistances of two types of connection (connection by four M2.5 bolts and impaction by wedged-block locking mechanism) are experimentally studied by comparison in this article. The thermal contact resistances using same locking method but adding different interface material (thermal grease, indium foil and thermal conductive pad) and the thermal contact resistances under different thermal densities are also studied. Results show that the thermal contact resistance of locking mechanism connection is smaller than that of bolt connection; the thermal contact resistance is smaller when interface material are added; among the interface materials, the thermal contact resistance while adding thermal grease is the best and indium foil is the worst.