In sound field visualization systems, imprecise spatial position and angle relationship between the microphone array and camera could lead to the error of the sound source localization. However, few of the previous studies have considered the spatial relationship between the camera and microphone array in sound field visualization systems. So there lacks a simple and effective spatial relationship calibration method for the spatial relationship between the camera and microphone array. In this paper, the calibration method for calculating any spatial orientation and position relationship between microphone array and camera is proposed, which can effectively eliminate the sound source localization error caused by the mismatched spatial relationship between the microphone array and camera, and then improve the precision of the sound source localization for sound field visualization system. Through minimizing the sound source localization errors of the known sound source in multiple positions, the spatial position and orientation between the camera and microphone array could be calculated respectively with stepped iteration calculation. Simulation and experiment results both show that the proposed method can accurately calculate any spatial orientation and position relationship between the camera and microphone array in a sound field visualization system, and could effectively improve the sound source localization accuracy of sound field visualization systems. The proposed spatial relationship calibration method could be used in various sound field visualization systems, and has an active significance for improving the sound source localization accuracy of sound field visualization systems.