Based on the LP (Layer Peeling) algorithm, the important influence factors on the reconstruction precision of the Fiber Bragg Gratings non-uniform strain, including the demodulation range of FBG non-uniform strain, the characteristic parameters of LP algorithm and the Fiber Bragg Gratings structure parameters, were numerically analyzed. From lots of simulating experiments, the results show, that the best proper strain demodulation is less than 3 000 με of Fiber Bragg Gratings with normal working length of 5~30 mm, and keeping the fractional length of nearby 0.1 mm for LP reconstruction algorithm can obtain the best precision of strain reconstruction. Remaining above conditions, it is found that the non-uniform strain reconstruction error is smaller when the refractive index modulation decreases, and for the strong grating, the refractive index modulation amplitude of approximate 0.000 12 is the best choice in Fiber Bragg Gratings non-uniform strain sensing. The results obtained here have certain guiding significance for improving the accuracy of Fiber Bragg Gratings non-uniform strain reconstruction.