The invention relates to a bonding agent for electronic packaging, and belongs to the field of electronic packaging. The bonding agent is prepared from granular substances, and is characterized in that the granular substances comprise three layers, an inner core is copper or copper alloy, a middle layer is tin or tin allay, an outer layer is colophony. The invention also relates to a preparing method of the bonding agent. Compared with the prior art, the bonding agent has the high melting point, the cost is low, the good conductive and heat conduction effects can be achieved, and meanwhile the bonding agent has the high viscidity.