The parameter control method is utilized to carry out the experimental investigation on laser trepanning of GH4037 superalloy and the trend in the effects of pulse energy, defocusing amount, trepanning velocity, and trepanning times on the hole taper and entry-exit-hole diameter is achieved. The results indicate that the pulse energy and defocusing amount obviously influence the hole diameter and taper angle, while the trepanning velocity and trepanning times mainly influence the hole morphology. The larger the defocusing amount is, the larger the heat-affected zone, entry hole diameter, and taper angle are. Increasing trepanning times and selecting appropriate trepanning velocity (3-6 mm/min) are helpful to improve the hole quality, reduce the accumulations around hole aperture, and improve the hole roundness.