The paper is to report the pharmacokinetics of furosemide in rats living at plain area and high altitude.  After intragastric administration of furosemide (2.87 mg·kg⁻¹), serial blood samples (0.5 mL) were collected by retro-orbital puncture at 0, 20 min, 40 min, 1, 1.5, 2, 3, 4, 6, 8, 12 and 24 h, samples were determined by LC-MS/MS, and plasma concentration-time data were analyzed by DAS 2.0 software to get the related pharmacokinetic parameters.  The main pharmacokinetic parameters: area under curve (AUC), mean residence time (MRT), the biological half-life (t_1/2) and the peak concentration (C_max) of furosemide, were significantly increased at high altitude, the time to reach peak concentration (t_max) and clearance (CL) was significantly decreased.  This study found significant changes on the pharmacokinetics of furosemide under the special environment of high altitude.  This finding may provide some references for clinical rational application of furosemide at high altitude.