With the development of optical communication and optical networks, the optical data processing based on optical fiber has been investigated intensely. Several technologies of fiber dispersion based optical data processing are introduced, including time lens, time stretch based analog/digital (A/D) converter, fiber grating sensor′s wavelength demodulation, serial time-encoded amplified imaging, all optical integrator, convolution and correlation. Their principles, developments, advantages and disadvantages are discussed. The potential applications of optical data processing using modal dispersion are also discussed through comparing chromatic dispersion and modal dispersion and two kinds of modal dispersion based optical data processing are introduced.