The parameters of storage battery performance reflects itself, has very important significance for the normal operation of the electrical equipment, in order to measure the battery parameters online and accurately, using a field programmable gate array (FPGA) designed a detector of battery parameters as the core. The AC injection is used to measure the resistance of the battery, LTC2943 to measure battery voltage, charge and discharge current, temperature and residual energy parameters. The old battery internal resistance were measured and compared to a new battery, and other parameters of single battery were tested. the results show that this design has the advantages of convenient use, high reliability, high measurement accuracy, and has high practical value.