Conventional wet-process phosphoric acid (WPA) extraction route encounters unsatisfactory extractionefficiency, phosphorus yield, and raffinate utilization. Herein, a new extraction route for H3PO4 separation from wetprocesssuperphosphoric acid (WSPA) is proposed to improve these dilemmas. We focus on the equilibrium of H3PO4extraction by tributyl phosphate (TBP) from WSPA and the extraction mechanism of TBP under high H3PO4 loadingconditions. Several critical factors affecting the extraction equilibrium were investigated to optimize the extraction process,including the initial phase ratio (R0), the volume fraction of TBP in extractant (TBP), temperature (T), and thecrosscurrent extraction stages. The results show that the single-stage extraction rate of H3PO4 reaches 70% at R0=6,TBP=80% and T=80 oC with separation factors P/Fe, P/Al, P/Mg, and P/Ca of 12.48, 21.66, 47.57, and 8.89, respectively. In addition, Fourier transform infrared spectroscopy and Raman spectroscopy enlighten the extraction mechanism athigh loading conditions. The characteristic peak positions of P=O, P=O…H2O, and P=O…H3PO4 in the infraredspectra are determined to be centered at 1,283, 1,267, and 1,233 cm1, respectively. The semi-quantitative analysis impliesthat the self-polymerization behavior of the extraction complex TBP·H3PO4 and the mutual attraction of reversemicelles (RMs) through their polar cores is the trigger for the formation of a third phase. Furthermore, the red shift ofP-(OH)3 asymmetrical stretching vibration in the Raman spectrum indicates the formation of hydrogen bonds amongH3PO4 molecules in the organic phase, which corroborates the formation of RMs. Conclusions can be obtained thatH3PO4 enters the organic phase under high loading capacity by reversed micellar extraction. The feasibility of thisextraction process is further tested by scrubbing, stripping, and cycling performance experiments. The results arepromising for the design of a new efficient route for separating H3PO4 from WPA.