The invention discloses a microcomputer relay protection test system based on measurement modularization. The microcomputer relay protection test system comprises a microcomputer relay protection device, a host, a power generator and an electric quantity collector. In the host, all devices in an electric power system are modeled and then connected with each other. After that, the operation simulation is carried out and faulty electric quantity data are obtained. The faulty electric quantity data are processed through adopting the analog tracking algorithm. The data are sent to the data receiving end of the power generator, and then the power generator reads the data and outputs pseudo-fault electric quantity data. The data are sent to the microcomputer relay protection device. The electricquantity collector conducts real-time sampling on the data of the power generator and the data after being subjected to the microcomputer relay protection device, and transmits data to the host afterthe sampling operation. The host processes the data and displays the data on a display screen. In conclusion, the invention provides an algorithm capable of simulating the electric quantity signals of a power grid, a method for determining the working precision of the microcomputer relay protection device based on the feedback idea and a set of relay protection device test system.