We have demonstrated efficient soft x-ray generation from femtosecond laser plasma created on a neodymium-doped glass target. Nd ions doped in glass target enhanced soft x-ray emission near 8 nm without broadening the soft x-ray pulse duration when there is no prepulse. A weak prepulse caused strong enhancement in soft x-ray intensity at 8 nm. By introducing a prepulse at 50 ns before the main pulse, 1&percent; energy conversion efficiency from laser pulse into soft x-ray at8±0.5 nmwas achieved by using a neodymium-doped glass target. This value is 1.2 times as high as that for Nd metal target case. ©1998 American Institute of Physics.