As the expansion of the power grid, many small power grids in remote areas with small generators and light loads are connected to the main grid through very long transmission lines. Once such a small power grid is split from the main power grid due to a certain fault, over-frequency and overvoltage is very likely to occur due to its excessive real power or capacitive reactive power, which could damage power equipments and local loads. First, the mechanism of over-frequency and overvoltage and their interaction in an isolated small power grid are analyzed. And then the influences of generator speed governor and excitation system as well as load characteristics on over-frequency and overvoltage are also introduced. Finally, a new suppression strategy is proposed for over-frequency and overvoltage of the isolated small power grid in remote area. Simulation results verify the effectiveness of the proposed suppression strategy.