Taking into account the loss and the second-to fourth-order dispersions,the condition and gain spectra of modulation instability induced by cross-phase modulation in different dispersion regions of optical fibers are analyzed when the perturbation frequencies of the two optical waves are equal and unequal, respectively. The results show that, the third-order dispersion will not influence the condition and gain spectra of cross-phase modulation instability,but will contribute to the effective wave number of the optical perturbation. In comparison with modulation instability of the mere second-order dispersion,when the second-and fourth-order dispersions have the srnae sign,the existence of the fourth-order dispersion makes an extra gain spectrum appear which is far away from the zero point. Depending on the different size relations of the two perturbation frequencies,the extra gain spectrum may consist of two small spectra or a single spectrum. The widths and the peak gains of the two regions of gain spectra will also vary with the size relations of the two perturbation frequencies. When the second-order dispersions of the two optical waves have the opposite signs, the existence of the fourth-order dispersion still makes a gain spectrum appear which is far away from the zero point.