Distribution of soluble reactive phosphate (SRP) in pore waters is a sensitive indicator showing geochemical properties ofphosphorus in sediments. Concentration of SRP in synthetic solutions was obtained based on the principle of diffusive equilibration inthin films (DET). Analytical procedure generally includes equilibration of the gels in solutions or pore waters, section of the gels afterretrieval, back elution of phosphorus in the gels, and analysis of SRP in the eluents. Equilibrium and extraction times weredetermined at 24h and 16h, respectively, with 0.25mol/L HNO₃ used as an extractant. Concentrations of SRP in pore waters ofdifferent sediments measured by using the established DET technique agree well with its actual values, and the variations aregenerally within ±5%. Analytical results for sediment profiles with this technique, which has a vertical resolution at about 3mm, alsoshow comparison with those using sampling techniques of Rhizon and Mini-Peeper. The established DET technique was used tomeasure SRP profiles in sediments of macrophyte- and algal-dominated regions in Lake Taihu. Peak-shape distribution and horizontalheterogeneity of SRP were observed in macrophyte-dominated region, while an upward and increasing movement of SRP wasobserved in algal-dominated region with an increase in water temperature.