The invention discloses a deck chair capable of automatically adjusting sleeping postures according to brain wave electrical signal characteristics. The deck chair comprises a chair seat, a chair backis movably connected to the right side of the chair seat, and a supporting seat is fixedly connected to the bottom of the chair seat, and the invention relates to the technical field of deck chairs.When the deck chair capable of automatically adjusting the sleeping postures according to the brain wave electrical signal characteristics lies down, a user pulls a sliding frame upwards to drive an adjusting rod to slide upwards, fixing of a foot supporting plate is lost, and a push plate is pushed through feet so as to drive the foot supporting plate to slide outwards, so that the extension length of the foot supporting plate can be freely adjusted, the most comfortable size can be selected according to the height of the user, and the problem that the existing deck chair can only adjust theangle of the chair, the length of the chair is fixed when lying down, the length of the deck chair cannot be adjusted according to the height of the user when the use rests on the deck chair, and whenthe deck chair is in use, the length of the deck chair and the height of the user are not matched, so that the use comfort is reduced is solved.