A stable, single-longitudinal-mode, nanosecond-pulsed Nd:YAG laser with a laser-diode dual-end pumping arrangement is constructed. Injection seeding is performed successfully by utilizing a RbTiOPO4 crystal as the intracavity phase modulator to change the optical length of the slave cavity based on the delay-ramp-fire technique. The laser generates 9.9 mJ of pulse energy with a 16 ns pulse duration at a 400 Hz repetition rate. A near-diffraction-limit laser beam is achieved with a beam quality factor M2 of approximately 1.2. The frequency jitter is 1.5 MHz over 2 min, and the fluctuation of the output pulse power is 0.3% over 23 min.