A three-direction decoupling type single stage suspension assembly arranged in the same direction is characterized by comprising three springs, wherein the three springs are placed vertically and arranged in the longitudinal direction; a spiral steel spring is arranged in the center of the assembly and is used for bearing vertical load and providing vertical rigidity; the two rubber springs are positioned on two sides of the spiral steel spring and are centrosymmetric along the spiral steel spring; one of the rubber springs is used for positioning an axle box in the longitudinal direction andproviding longitudinal rigidity; and the other rubber spring is used for positioning the axle box in the transverse direction and providing transverse rigidity. Separation of vertical rigidity, longitudinal rigidity and transverse rigidity of a single stage suspension is realized, and rigidities in three directions are decoupled; and furthermore, the diameter of a single spring is greatly reduced,therefore, occupation of the springs to the transverse space of a bogie is relieved, and space arrangement of the internal bogie of the axle box is facilitated greatly.