To analyze the effect of confining pressure on the stress intensity factors (SIFs) determined by the cracked Brazilian disk, the weight function method is employed to obtain the closed-form expressions of SIFs under various confining pressures; and the explicit expressions of the SIFs subjected to both the confining pressure and diametrical force are obtained. Based on the expressions of the SIFs, the effects of confining pressure on SIFs of the cracked Brazilian disk are analyzed. It is shown that the confining pressure has no effect on the SIF of mode II; and the crack subjected to pure confining pressure always tends to close up. The SIF of mode I decreases with the increase of confining pressure when the cracked Brazilian disk is subjected to the combined effect of confining pressure and diametrical force. By comparing the numerical results and theoretical results, it is found that two results are in good agreement, indicating the validity and reliability of the theoretical analysis. In addition, the effect of confining pressure on the loading conditions is also analyzed for pure mode II crack. The results show that the critical loading angle for pure mode II crack decreases with the increase of confining pressure, and gradually tends to 0 degrees. Therefore, the crack generated at about 0 degree of the loading angle is not always the pure mode I fracture at a high confining pressure.