A simple and precise high-performance liquid chromatographic (HPLC) method has been developed for analysis of flavonoids in Lamiophlomis rotata. HPLC conditions were optimized. Baseline separation was achieved by use of a binary gradient prepared from 100:0.2 (v/v) water-trifluoroacetic acid (component A), and acetonitrile (component B). The gradient was from 20 to 35% B in 10 min, hold at 35% B for 20 min, then from 35 to 70% B in 10 min. The injection volume was 10 μL, and the detection wavelength was 366 nm. Linearity and precision were investigated. When normal least-squares linear regression (LSLR) was compared with weighted least-squares linear regression (WLSLR), values obtained by use of the latter were much closer to the actual values, over the whole range of concentration, than those obtained by use of the former. WLSLR was therefore used in this work. This HPLC method was successfully used for analysis of the flavonoids in Lamiophlomis rotata and could be effective for quality control of the plant.