The invention discloses a marine diesel engine starting protection method and belongs to the field of diesel engines. The marine diesel engine starting protection method can protect a diesel engine starter against long-time large-current supply, effectively avoid the condition that the starter is burnt down or damaged due to heat emitting, and effectively protect the starter against gear rolling caused by secondary starting; meanwhile, by combining the pre-supply process into the starting process, the starting process of the marine diesel engine is simplified, and it is ensured that the dieselengine is started after being fully lubricated; besides, an emergency starting button (SB2) is additionally arranged, and a starting protection contact is connected in a starting circuit in series, in other words, normal starting can be achieved in the situation of a failure of a staring button or a starting relay; and meanwhile, under the arrangement of a layer variant conduction contact, the situation that conduction of the circuit becomes poor as oxidation caused by conduction heat emitting is effectively relieved, the sensitivity of a whole starting protection logic control unit is effectively improved accordingly, and the effect of starting protection of the diesel engine is achieved.