The basic theory of STD（Spare Time Domain） algorithm is introduced

and the algorithm is improved

based on which

the concrete implementation steps of parameter identification for low-frequency oscillation are given.The validity and practicality of the improved STD algorithm are verified by the time domain simulation data of a 16-generator system and the PMU（Phase Measurement Unit） data of a practical power grid. The comparison of identification results among the improved STD algorithm

the TLS-ESPRIT（Total Least Square-Estimation of Signal Parameters via Rotation Invariance Techniques） and ITD（Ibrahim Time Domain） algorithm shows that the improved STD algorithm performs well in the aspects of accuracy and anti-noise performance

and it can realize accurate identification without low-pass filtering of the input signal compared with the multi-channel ITD algorithm with low-pass filter.