The invention discloses a steam turbine flow curve identification and optimization method based on power value calculation. The method includes the following steps that firstly, a plurality of sampling test points are set, and real-time working condition data are collected; secondly, vacancy working condition data and abnormal working condition data are deleted; thirdly, an output power value, a main steam pressure value and a total valve position value are selected to continuously stabilize the real-time working condition data of a plurality of sampling periods, and mean value treatment is carried out on various parameters; fourthly, a target data set is mined through the K-central point algorithm; fifthly, on the basis of power value calculation, a steam turbine adjustment valve bank flow characteristic curve under specific main steam pressure is identified; and sixthly, a steam turbine adjustment valve bank flow characteristic curve under rated main steam pressure is extracted, and a sector with unreasonable linearity is analyzed and optimized. The steam turbine flow curve identification and optimization method can be used for identifying the actual flow characteristic curve under the specific main steam pressure of a steam turbine adjustment valve bank, so that the specific adjustment valve bank flow characteristic curve is consistent with the actual curve, and safe and stable operation of a steam turbine unit is guaranteed.