Background: Most researches were focused on chemical constituents and bioactivities of Pedicularis. However, there were a few reports on simultaneous determination of the series phenylpropanoids compounds in Pedicularis by High Performance Liquid Chromatography (HPLC). Objective: To establish an HPLC method for simultaneous determination of salidroside, verbascoside, iso-verbascoside, leucoseptoside A, jionoside D and martynoside in Pedicularis densispica (PD), and to assess the enhancing exercise ability of effective fractions of phenylpropanoids (EFP). Materials and Methods: The separation was performed on C18 column with step-wise gradient elution with water (A)-methanol (B) as the mobile phase at a flow rate of 1.0 mL/min, with detection wavelength at 275 nm (0–4 min) and 330 nm (4–40 min). The EFP were obtained from extracts of PD by resin gradient dilution. The enhancing exercise ability of EFP was exerted in exhaustive swimming and anoxia endurance tests in vivo. Results: The contents of six marker compounds had good linear relationship in the ranges of 2.10–8.40, 13.60–54.40, 0.93–3.72, 0.53–2.12, 1.50–6.00, 0.37–1.28, respectively, and the average recoveries of the six phenylpropanoids were all in the range of 98–103%. Total contents of phenylpropanoids in EFP were more than 60%. Three medicine groups of exhaustive swimming and anoxia endurance time were higher than those of the water group. Conclusion: The analytical method is reliable, simple and accurate, and can be used for the comprehensive quality control of PD. This experiment suggests that PD has the effect of promoting the recovery and elimination of fatigue and improving the exercise capacity.