Earth pressure of finite soil will arise when the backfill width behind retaining structure is limited. Seismic active earth pressure is the primary load for retaining wall design in earthquake areas. Existing seismic earth pressure calculation theory which is suitable for semi-infinite fill does not apply to calculating seismic earth pressure of finite backfill. Seismic inertia force is caculated with pseudo-dynamic method, and differential equations for seismic active earth pressure of finite backfill are established with horizontal differential element method considering soil arching effect.Comparisons and analysis of the analytical results and experiment results are performed as well as other theoretical solutions, and the rationality of the proposed method is verified. By analyzing the main parameters, the distribution rules of seismic active earth pressure of finite backfill are revealed. The results show that the most disadvantage combination of seismic inertia force direction is that Q_v is vertical downward and Q_h is horizontal towards the retaining wall. The parameter analysis discusses the effects of horizontal seismic coefficient, finite backfill width, fill cohesion, internal friction angle and wall-soil friction angle on the seismic active earth pressure coefficient and distribution. The proposed calculation method can