The space vector modulation (SVM) and double line voltage modulation (DLVM) for matrix converter are compared. The two modulations are proved to have the same duty-cycle. DLVM is a special modulation sequence of SVM which has one zero-vector in the middle of modulation sequence. Both two modulations can detect unbalanced input voltage real-time and generate balanced output voltage. But SVM with suitable zero vectors can further eliminate short PWM pulses and compensate output voltage at low modulation index. The switching loss of the two modulations is analyzed. The high differential voltage consists in the middle of the SVM modulation subsequence which will cause high switching loss in the commutation before or after the high differential voltage. However, DLVM has lower switching loss than SVM because DLVM modulates according to the order of the magnitude of the input voltages. The choice between SVM and DLVM depends on request of eliminating short PWM pulses or reducing switching loss. The two modulations can be alternatively used to show both merits.