Abstract: The present invention provides a trash bag closing mechanism, including: a transmission assembly which includes a power unit and a scissor-hinge unit; a first guide plate arranged on the scissor-hinge unit; a second guide plate arranged opposite to the first guide plate; where the power unit is used to drive the scissor-hinge unit to expand and contract, which consequently drives the first guide plate to slide toward the second guide plate to realize the closing and opening of the trash bag; and a heat sealing assembly arranged on the first guide plate and/or the second guide plate and used for heat sealing a closed trash bag. The range-extending effect of the transmission is realized through the scissor-hinge unit, reducing the energy consumption of operation and achieving the effect of energy saving.