The invention discloses a circuit data processing method and a circuit data processing device. The method includes the following steps that circuit data are divided into different data units and stored into an on-board device in advance; when received, response data transmitted by responsers are parsed, so that the identification information of the responsers is obtained and used as target identification information; the data units matched with the target identification information are searched to be used as target data units; the data of the target data units are used as current circuit data. Thus the method and the device can be adopted to increase the efficiency of the on-board device in obtaining circuit data.