Abstract: In the report, adjusting factors such as anthrone solution dosage, reaction temperature, and reaction time was performed. The anthrone sulfuric acid method were systematically optimized to detect the soluble sugar content in seagrass leaves. Based on these parameters, the effects of four drying methods (60 ℃ drying, air drying, silica gel drying, and freeze drying) and two extraction methods (water bath extraction and ultrasonic extraction) on soluble sugar extraction were compared and analyzed. The results indicated that the optimal sensitivity and accuracy were achieved when 0.2 mL of sample extract was combined with 1 mL of anthrone-sulfuric acid solution, the reaction temperature was 95 ℃, the reaction time was 6.5 minutes, and the detection wave length was 624 nm. The extraction efficiency was obtained when drying at 60 ℃ was followed by water bath extraction. The method is simple to execute, stable, and requires a minimal sample size, which makes it ideal for the rapid analysis of large-scale seagrass samples and offers the reliable technical support for the ecological research on seagrass.