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When multiple T-type three-level photovoltaic grid-connected inverters with common AC bus and DC bus are operating, the circulating current takes place among the parallel-connected inverters due to the line impedance difference, non-synchronized operation of switching devices and inconsistency of comprehensive parameters. The following methods are proposed in this paper, control strategy based on virtual impedance is discussed to inhibit circulating current caused by the different line impedances; Self-synchronization control method based on zero-crossing of grid voltage and synchronous modulation PWM is presented to restrain circulating current caused by non-synchronized operation of switching devices; Control strategy based on feed forward control of zero-sequence current is studied to inhibit circulating current caused by inconsistency of comprehensive parameters. These control method are discussed in detail, experimental results verify that control strategy of zero-sequence circulating current is right and feasible.