The invention relates to a preparation method of a three-dimensional porous copper/graphene composite current collector for a secondary metal lithium battery negative pole. The preparation method includes: putting a nano porous metal foil into a quartz boat, and calcining for 0.5-5min at temperature of 800-1000 DEG C in an atmosphere of argon and hydrogen; feeding ammonia gas, acetylene, argon andhydrogen, and allowing reaction in the condition for 2-10min to obtain the three-dimensional porous copper/graphene composite current collector. The invention further provides a method of utilizing the current collector to prepare the metal lithium negative pole.