The invention relates to a mold surface quenching device and a method. The mold surface quenching device comprises a mobile device of which the upper surface is used for fixing a mold, wherein a sensor is arranged above the mobile device, the shape of the sensor is similar to the surface shape of the mold to be quenched, the sensor is fixedly connected with a bus bar, the bus bar is fixedly connected with a quenching transformer, and the quenching transformer is connected with an intermediate frequency power supply through a cable; the sensor is provided with a hole I which is communicated with a coolant inlet pipe and a hole II which is communicated with a coolant return pipe; and coolant injection holes are uniformly distributed at the back end of the sensor. The invention also comprises a quenching method using the mold surface quenching device. The invention has the advantages of simple structure, convenient operation, good quenching quality and high efficiency.