A linear light source module comprises a holder, a first light guide, a second light guide, a first light-emitting element and a second light-emitting element. The first and second light guides are mounted on the holder and arranged in series, where the first light guide has a first emitting surface and the second light guide has a second emitting surface. The holder partially surrounds the first and second light guides. The first light-emitting element is disposed close to a first end of the first light guide, and a light beam emitted by the first light-emitting element is reflected and converted by the first light guide into first linear light emitted from the first emitting surface. The second light-emitting element is disposed close to a first end of the second light guide, and a light beam emitted by the second light-emitting element is reflected and converted by the second light guide into second linear light emitted from the second emitting surface. An optical assembly for a scanner using such linear light source module is also disclosed.