The invention discloses a WAMS dynamic data based network source coordination online monitoring and assessment system. The system comprises a primary frequency modulation monitoring module, an excitation system evaluation module, an AGC performance evaluation module, a wind power integration online monitoring module and a subsynchronous oscillation monitoring module. The primary frequency modulation response situations in daily and large-disturbance conditions are subjected to real-time statistics; a real-time operation state of a power generator, the low frequency oscillation suppression capability of a PSS of an excitation regulator, the operation alarming and limitation of the excitation regulator, the state and excitation pressure regulation of an excitation system and the like are calculated and assessed; indexes such as an AGC regulation rate, AGC regulation precision, AGC regulation time and the like of a power generator unit as well as grid-connection indexes such as an active power maximum variation of a wind power plant, high and low voltage ride through of a wind power unit, a frequency change of the wind power plant, voltage fluctuation of a grid-connection point and the like are calculated and analyzed; and a subsynchronous oscillation event is pre-warned. According to the system, auxiliary tools and convenient means are provided for power grid dispatching operation personnel to quickly locate network source coordination problems.