With the increasing penetration rate of new energy units in power system, the inertia level of power system decreases obviously, which leads to the threat of system frequency stability, so it is of great significance to evaluate the inertia level of power system effectively. In this paper, a method of node equivalent inertia evaluation for new energy power systems based on Kalman filter algorithm is proposed. Firstly, the calculation method of inertia of new power system containing new energy units is derived, and the relation of frequency-power-inertia is clarified. Secondly, Kalman filter identification algorithm is used to fit the frequency and power measurement data of each node of the power system, and the corresponding inertial time constant of each node is identified based on the fitting results. Finally, the effectiveness and feasibility of the proposed evaluation method are verified in the improved IEEE39-node system.