The actress claimed that the stalker has threatened to kill her.
After posting a picture on her Twitter page of the alleged stalker on the grounds of her home - which she has now taken down - Lohan wrote: "This is the freemason stalker that has been threatening to kill me - while he is TRESPASSING!
"I'm actually scared now- the blood in the 'cults' book was too much."
According to gossip website TMZ, Lohan has insisted that the man has been obsessed with her for nearly four years and often visits her home to leave her strange gifts.
She also said that he has sent her "insane" text messages during this period and she now intends to take the matter to the police.
Lohan, who recently received a 120-day prison sentence for probation violation, has reportedly told friends that she will stay sober for the rest of her life.