In order to avoid override trip or protection reclosure in practical running process and ensure power supply safety of coal mine highvoltage grid, this paper gives a testing algorithm of overcurrent protection in coal mine highvoltage grid based on sparse matrix, it combines overcurrent protection testing algorithm and sparse matrix, obtains power supply relationship matrix between branch nodes, gives computing methods of fault current, acquires final switch matrix that needs to execute trip operation, and executes trip operation for corresponding switch in coal mine highvoltage grid diagram. According to consequence of switch trip, it can determine whether present overcurrent protection setting is reasonable or not.