A serial iterative co-channel interference cancellation scheme is proposed for the MFSK/FH-SSMA system. First, a soft-limiter is employed to formulate the received time-frequency matrix with multilevel entry to suppress the residual interference due to the co-channel interference cancellation. Secondly, a serial detection scheme is utilised to solve the ambiguity problem. Both the detection performance and the computation complexity are simulated to validate the applicability of the proposed scheme. It is unveiled that the proposed scheme could be utilised to improve the iterative interference cancellation scheme significantly with negligible increase in computation complexity. Moreover, the proposed scheme is able to achieve the maximum likelihood detection performance with much lower computation complexity.