In order to optimize laser ablation performance of a micro-thruster with 1U dimensions, which employs a micro semiconductor laser, the impacts of pulse width and glycidyl azide polymer (GAP) thickness on thrust performance was researched. The results showed that with a GAP thickness of 200 μm, the single-pulse impulse (I) increased gradually with the increase in the laser pulse width from 50 to 800 μs, while the specific impulse (Isp), impulse coupling coefficient (Cm), and ablation efficiency (η) all reached optimal values with a 200 μs pulse width. It’s worth noting that the optimal pulse width is exactly the ignition delay time. Both Cm and η peaked with the pulse width of 200 μs, reaching 242.22 μN/W and 35.4%, respectively. With the increase in the GAP thickness, the I and the Cm increased gradually. The GAP of different thickness corresponded to different optimal laser pulse width. Under a certain laser pulse width, the optimal GAP thickness should be the most vertical thickness of the ablation pit, and the various propulsion performance parameters at this time were also optimal. With the current laser parameters, the optimal GAP thickness was approximately 150 μm, the Isp was approximately 322.22 s, and the η was approximately 34.94%.