A simple bending sensor is performed with a novel insensitive long-period fiber grating (LPG). The characteristic of the insensitive LPG has been experimentally presented, which has the pitch and the notch wavelength of 440 μm and 1516.2nm at 20℃. We have investigated temperature and strain insensitivities. The temperature coefficient is about 0.003 nm/℃ from 10 to 50℃, and the strain coefficient is only about 15 nm/ε, which are about 1/30 and 1/100, compared with the corresponding coefficients of the conventional devices with typical values of 0.083 nm/℃ and 1521 nm/ε, respectively. It is fabricated as a bending sensor without any treatment to eliminate the temperature and strain effects, and the bending sensitivity is the same order as the ordinary one. At the same time, the temperature-and strain-insensitive LPG will have wide prospect for other smart fiber sensors and communication devices.