The invention provides a method of quickly responding to a trim command, an SSD (Solid State Disk) controller and a system. The method comprises the following steps: when the SSD controller receives the trim command issued by a host computer, the SSD controller acquires a logical address range signified by the trim command; the SSD controller modifies a state of a logical address signified by the trim command, and the state is set to be invalid; the SSD controller returns an answering signal meaning the trim command to be finished to the host computer; and after the trim command finishes the answering, the SSD controller selects a computer to modify a state of a physical address corresponding to the logical address, and the state is set to be invalid. According to the technical scheme provided by the invention, trim commands of multiple continuous large sections of data can be quickly executed, so that trim requests of the multiple large sections of data of the host computer are responded in a shorter period, the waiting time of a system is reduced and the command response efficiency is improved.