LPFGs written by high-frequency CO_2 laser pulses have great potential for use in optical fiber sensing and communication. It is of importance to study the fundamental characteristics of these novel LPFGs. In this paper, a more systematic analysis is carried out to investigate the resonant wavelength-bend sensitivity of the LPFG and its bend loss of resonant peaks based on the mode field theory. It is for the first time to our knowledge, that a method is proposed for analysis of the orientation-dependence of the bend of the LPFG. The simulation is in agreement with experimental results. This paper provides a more systematic analysis for the bend characteristics analysis of the LPFG written by the high-frequency CO_2 laser pulses exposure method.