We investigate the application of integrated micro-combs in RF photonic systems and demonstrate a microwave photonic intensity differentiator based on a Kerr optical comb generated by a compact integrated micro-ring resonator. The on-chip Kerr optical comb is CMOS-compatible and contains a large number of comb lines, which can serve as a high-performance multi-wavelength source for the transversal filter, thus greatly reduce the cost, size, and complexity of the system. The operation principle is theoretically analyzed, and experimental demonstrations of fractional-, first-, second-, and thirdorder differentiation functions based on the principle are presented.