The application of recycled fine aggregate to ultra-high performance concrete（UHPC） not only reduces its cost，but also realizes the resource utilization of construction waste.UHPC was prepared by pre-wet recycled fine aggregate（RFA）.The effects of particle sizes（0.6~<1.18 mm and 1.18~2.36 mm） and replacement rates（10%，20%，30% and 40% of volume fraction） of pre-wetted treatment RFA on working performance，mechanical properties，volume stability and chloride ion penetration resistance of UHPC were investigated.The mechanism was revealed by microhardness，TG-DTG，MIP and SEM.The results showed that the particle size and content of recycled fine aggregate were the key factors that determined the workability，mechanical properties and shrinkage properties of UHPC.With the increase of RFA content，the fluidity and autougenous shrinking of UHPC were decreased gradually.But its compressive strength showed a trend of increasing firstly and then decreasing，among which UHPC prepared with 20% pre-wetted recycled fine aggregate（particle size of 1.18~2.36 mm） showed better performance.Compared with the control group，the 28 days compressive strength was increased by 7.0%，while the autougenous shrinking was decreased by 78.8%.The pre-wetted RFA released water into the UHPC matrix，reduced the internal self-drying process，and improved the degree of hydration reaction，which optimized the interface composition structure，and thus refined the internal pores of the matrix.