The relaxor ferroelectric single crystals have a good application prospects for the piezoelectric devices because of excellent piezoelectric properties and temperature adaptability.But the cutting orientation has to be considered before design and manufacture of the devices due to the engineered domain configurations and anisotropy.This paper discussed the selection criterion of crystal orientation regarding the output voltage of piezoelectric vibration energy harvester starting from the needs of power supply of the Internet of Things.By computation,the optimized crystal orientations with larger faulttolerant regions were proposed for lead magnoniobate titanate single crystal poled along the pseudocubic ［001］、［011］ and ［111］ directions respectively.The sensitivity of these cutting orientation to the cutting angle error was analyzed.The relevant physical property tensors were given for the optimized crystal orientations.