Abstract: The effective compressive stress and prestress loss in manufacture and curing of larger-diameter prestressed high concrete(PHC) pipe piles were studied by a field experiment performanced for two pipes of PHC with 1 400 mm diameter and different lengths.Pasting the strain gauges on prestresed steel bars directly was used for testing the prestress for the first time, and the designed prestress and the distribution of different section in different manufacture stage were compared with the experimental results.The results showed that tensile stress of prestressed steel bar was a linear decreasing trend form tension section to anchor section after forming by centrifugal technics;the effective tensile stress of prestressed steel bar and the effective compressive stress of concrete in two pipes were much lower than the theoretical data.The loss of prestress of PHC pipe piles was much greater during releasing tension than during other process.the prestress distribution of each section was not uniform but the midsection was much better which had a increasing trend with time growth.