The invention discloses a secondary refining method capable of improving cleanliness of molten steel. The secondary refining method capable of improving the cleanliness of the molten steel comprises the steps of controlling the steel tapping temperature above 1650 DEG C and adding cover can lime at a ratio of 2-3 kg/t to steel after steel tapping; then conveying the steel ladle to an LF station and ensuring the inlet temperature be above 1570 DEG C, then adding hydrated lime at a ratio of 5-10 kg/t to steel from an overhead bunker at one time after the temperature and alloys are all adjusted,wherein the granularity of the hydrated lime is 0.2-0.5 mm, and conducting soft argon blowing operation for 3-5 min, and adding sluggish slag lime at a ratio of 3-4 kg/t to steel after argon blowing;and conducting vacuumizing operation for degassing a furnace after the steel ladle gets into a VD furnace and ensuring the dwell time, which is lower than 67 Pa, of the VD furnace be not shorter than25 min, then enabling inclusion in the molten steel to be taken out and float upward by bubbles generated by the hydrated lime, and conducting hydrogen determination, and directly pouring with a machine after soft argon blowing for longer than 5 min. By means of the method, the melting time would not be increased, the raw materials are low-cost and the operation is simple and practicable.