As a device without dc line, the ac line side abnormal inputs can deteriorate its output characteristics. The feed-forward compensation scheme for SPWM matrix converter is proposed. Tri-carrier is prior modulated by measured envelop of line voltages, to let the pulse width of SPWM get different compensation in each pulse. The scheme will be analyzed and implemented. Analyses and simulations show that the scheme modifies effectively output characteristics of MC (Matrix Converter) under abnormal input conditions.