Nd3+-doped phosphate glass amplifier with high gain and broad band is important in inertial confinement fusion (ICF) laser driver research. After analyzing all the factors which determine gain of a laser diode array (LDA) pumped Nd glass rod amplifier, the optimum parameters are presented. The ray-tracing model is set up to simulate the deposition process of LDA side-pumped Nd glass rod amplifier, and the relative program is developed. Based on the simulation, the structures of amplifiers without and with micro-lens are optimized. From the error analysis of LDA pointing, it is found out that the amplifier without micro-lens is more preferable. A rod amplifier with 2 mm Nd glass and 8.1 kW pumping power is manufactured. The fluorescence distribution of the amplifier is uniform. As pumping power is 7.7 kW, the amplifier gain is 40. When a polarizer is added behind the amplifier, gain of the amplifier is very stable.