A cosmetic pen a hollow outer body and a hollow inner body with an applicator and a lip stick unit are respectively connected to two ends of the hollow outer body. A transmission unit is located between the sleeve of the lip stick unit an the inner body. The sleeve includes an exterior threaded section which is engaged with a cap so that when rotating the cap, the cosmetic liquid in the inner tube can be pushed out from the applicator. The lip stick unit includes a base with a spiral groove and a lip stick is connected to the base, a sleeve is engaged with the spiral groove so that the base can be moved axially by rotating the sleeve to use the lip stick.