Abstract: OBJECTIVE To investigate the pharmacokinetics and bioavailability of naproxen choline ionic liquid in rats after intragastric administration. METHODS Naproxen choline ionic liquid was given to rats by intragastric administration. Blood samples were collected at different time points after administration. The blood samples were precipitated by methanol and then centrifuged, and then an Extend-C₁₈ column(4.6 mm×250 mm, 5 μm) was used. Methanol(A)-0.3% phosphoric acid aqueous solution(B) (74:26) was used as the mobile phase, the flow rate was 0.8 mL·min^-1, and the detection wavelength was 230 nm. Indomethacin and naproxen were used as internal standard and tested object in determination of naproxen choline ionic liquid in rat plasma. Pharmacokinetic parameters were calculated using DAS 2.0 software. RESULTS After intragastric administration of naproxen suspension to rats, its t_1/2α was 5.12 h, t_1/2β was 10.13 h, T_maxwas 2 h, C_max was 112.92 mg·L^-1, and AUC_(0-t) was 1 091.01 mg·L^-1·h. After intragastric administration of naproxen choline, its t_1/2α was 5.64 h, t_1/2β was 69.32 h, T_max was 1 h, C_max was 135.97 mg·L^-1, AUC_(0-t) was 1 305.79 mg·L^-1·h, and the relative bioavailability was 119.686%. CONCLUSION After intragastric administration of naproxen choline to rats, the peak concentration and bioavailability of the naproxen in vivo are higher than those of the common suspension, and the peak time is earlier.