The key issues of phase measurement unit（PMU） based parameter identification are studied， including identifiability analysis of parameters， selection of disturbance types， measurement data filtering of PMU， and impacts of permanent bias in power angle measurement on parameter identification. Firstly， condition number of matrix H is taken as the index which can quantitatively describe identification condition. The index can consider the influence on identifiability brought by both model structure and degree of disturbance. Secondly， the fact that positive sequence component derived from asymmetric disturbance in power system can be used for generator parameter identification， is verified by both theory analysis and numeric test using measured disturbance. Some suggestions for disturbance selection are given according to the depth of fault. Then， a kind of zero phase-shift filtering method is introduced to overcome phase shift brought by traditional digital filter. Finally， power angle measurement methods are summarized， and the effect of permanent bias exists in measured power angle to identification result is analyzed. Test results of some actual case studies demonstrate the validity of the proposed method.