The magnetic sensor array Honeywell HMC1043 was used to collect the magnetic information of the permanent magnet. Because the precision of the system is directly affected by sensor parameters including the position, the direction and the sensitivity coefficient of the sensor array, the accurate calibration of the magnetic sensors was indispensable to obtain the accurate sensor parameters of the sensor array in the magnetic tracking system. A method of objective error function and optimization calculation for the problem of magnetic sensors calibration was proposed in this paper. The error function was minimized through updated parameters and iterative calculation. Then the accurate location, direction and sensitivity coefficient of the sensors array were obtained. This method was applied to the actual sensor system. In MATLAB environment, the position, the direction and the sensitivity coefficient of the sensor array were determined through calculation and the magnetic information of the permanent magnet was collected by the computer to realize calibration. By this method, the accuracy of the system localization was improved significantly, which therefore verified the feasibility and rationality of the algorithm.