The present application relates to the technical field of films and television lighting, and provides a lamp and an optical lens thereof, the lamp includes: a lamp body, a first housing and a second housing, the first housing is provided with slots, the second housing is movably sleeved inside the first housing, and an outer wall of the second housing is provided with a protruding member extending through the slots, the protruding member further simultaneously moves relative to the second housing while moves in the slot, to adjust a distance between the second housing and the lamp body. When the protruding member moves in the slot on the first housing, a part of the protruding member can also move relative to the second housing at the same time.