Abstract: A simple cavity design for a pulsed Nd:YAG laser employed a 1mm-diameter laser rod pumped by a single laser diode module was reported.An experiment was performed to optimize the cavity design to obtain a laser output of 10W average power and a nearly diffraction-limited TEM00 mode.In this design,the small-diameter laser rod was used to eliminate the oscillation of high-order transverse modes,and a combination of a curved rear mirror and a negative lens placed inside the cavity was employed to compensate the thermal lens effect inside the laser rod.By experimentally optimizing the values of curvature of the rear mirror,the focal length of the negative lens,and the cavity spacing to maximize simultaneously the output power and the beam circularity,the pulsed Nd:YAG laser reached an average power of 10.8W,a beam circularity of 98.8%±0.8%,and M2 value of 1.1.The experimental results showed that in laser engineering the small-diameter laser rod could be used to improve the beam quality of high-power lasers.