Equalization technique is an usual way to solve the inter-symbol interference problem in communication system. The dual-mode modified multi-mode algorithm and modified decision directed algorithm were combined in the fractionally-spaced equalizer to improve the performance about convergence speed and steady residual inter-symbol interference which produced by traditional constant modulus algorithm. The dual-mode was used to adjust equalizer, and the equalizer was further adjusted by switching to decision directed algorithm. And fractionally-spaced equalizer solves the spectrum aliasing problem, caused by baund-spaced equalizer because the sampling rate is not high, thus the performance of equalizer was further improved. Monte Carlo simulation shows that the algorithm has fast convergence with lower residual ISI.