We demonstrated an actively acousto-optic Q-switched pulsed laser based on Pr:YLF at 604 nm. A 604 nm continuous-wave (CW) laser with maximum output power of 3.84 W was achieved for the first time. The Q-switched laser with a maximum average output power of 0.384 W, a narrowest pulse duration of 44.5 ns, a maximum single pulse energy of ~64.1 μJ, and a maximum peak power of ~1.44 kW were obtained at a repetition rate of 6 kHz. To the best of our knowledge, this was the first report of such narrow pulse duration, high power and high energy Q-switched pulsed laser at 604 nm. The beam quality M2 x and M2 y factors were measured to be 2.87 and 2.40 respectively. The results shown that acousto-optic Q-switching was a promising method to obtain pulsed lasers.