The present disclosure discloses a multichannel PIM digital cancellation circuit, including a first frequency-shift variable rate module, a second frequency-shift variable rate module, a first conversion circuit, a second conversion circuit, a duplexer, a second transmission duplexer, a channel combiner, a third conversion circuit, a cascaded filter circuit, a PIM canceller, a feedback circuit, and a first adder. The cascaded filter circuit compensates for channel responses such as a delay difference or a phase difference generated after a transmit signal passes through a digital domain downlink, a digital-to-analog converter, and an analog domain downlink; the cascaded filter circuit simulates a group delay unevenness characteristic of the duplexer in the multichannel PIM digital cancellation circuit; a cascaded filter fits an S parameter of the channel combiner in the multichannel PIM digital cancellation circuit, and precisely fits a combining process of the channel combiner in a digital domain, so that a signal capable of canceling a PIM interference signal of a multi-transmission and multi-reception inter-mediate radio frequency system that includes the channel combiner is finally generated in the present disclosure.