In this paper, we investigate the effect of the fiber dispersion compensation and dispersion slope compensation in 160Gb/s single channel optical fiber transmission systems. Different dispersion maps are analyzed and their transmission performances are compared by calculating the Q factor. The numerical results show that there is no significant difference in the performance between the systems with and without dispersion slope compensation for the dispersion managed transmission systems when the launch power and the pre-compensation fiber length are all optimized. So, we conclude that the compensation for dispersion slope is not a must for dispersion managed fiber transmission systems. However, for the systems consisting of a single transmission fiber, the performance can be significantly improved by dispersion slope compensation. Moreover, the effect of local dispersion on the transmission performance is studied and the system performance improves slightly with higher local dispersion.