A method is proposed to directly inscribe long period fiber gratings(LPFGs) in coated standard communication optical fibers by an 800 nm infrared femtosecond laser. Influence of fiber coatings on the effective indices for fundamental core mode and cladding mode was analyzed theoretically, as well as the LPFG’s temperature sensitivity. Temperature performance of the low-order cladding mode of uncoated and coated LPFGs was tested, respectively. The results show that the presence of coating is not only the desirable protective layer for LPFGs, and most importantly, the LPFG’s temperature sensitivity is increased to 0.1173 nm/°C, in accordance with the theory analysis. The coated LPFGs, if as temperature sensors, will have a good mechanical strength and temperature sensitivity.