Single-phase polycrystalline Sr2Ru1-xCoxO4 are successfully synthesized by conventional solid-state method with doping content up to x = 0.25. Ferrimagnetism develops among the incommensurate antiferromagnetic fluctuations in the doped compounds. An abnormal coercivity-temperature relation at a high doping level (x > 0.10), in which the samples have smaller coercive field at low temperature than that at high temperature, i.e., H-C(5 K) < H-C(50 K), is observed. The Curie-Weiss temperature shows the negative value for all samples, and the susceptibility increases with Co doping content x. The exchange bias effect is detected in magnetic hysteresis loops. A three-dimensional transport property has been derived based on the variable rang hopping theory, indicating a thermally assisted hopping of electrons between the localized states.