We report a reflection-based phase-shifted long period fiber grating (PS-LPFG) and demonstrate its capability for simultaneous measurement of temperature and external reflective index (RI). The sensor device comprises a grating directly written by CO2 laser and silver-coated end face. A π-shifted LPFG is presented with two attenuation bands through its reflection spectrum. These two bands have different sensitivity towards temperature and external RI that can be used for simultaneous measurement of the two variables. The experimental results show that this probe-type PS-LPFG performs well in terms of linearity and sensitivity.