Objective  To investigate early changes in anterior chamber parameters with the Allegro Oculyzer system after laser in situ keratomileusis （LASIK）. Methods  Thirty-nine patients （77 eyes） were recruited for this prospective self-control study. An Allegro Oculyzer anterial segment analysis system was used to measure the parameters of the anterior chamber （i.e. the anterior chamber volume， the anterior chamber angle of the four quadrants， and the central and peripheral anterior chamber depths） before and after LASIK. The Wilcoxon signed rank test was used for data analysis. Results  Before surgery， the posterior corneal tangential curvature， the anterior chamber volume， the anterior chamber angle（average/superior/inferior/nasal/temporal）， and the central and peripheral anterior chamber depths （superior/inferior/nasal/temporal） were： 6.19±0.23 D， 207±30.2 mm3， 40.4°±4.53°， 33.8°±8.57°， 33.9°±4.72°， 42.9°±5.00°， 42.9°±4.68°， 3.23±0.23 mm， 1.51±0.20 mm， 1.43±0.24 mm， 0.98±0.20 mm， and 1.03±0.21 mm， respectively. Seven days after the surgery， the parameters had changed to： 6.19±0.22 D，197±31.1 mm3， 40.6°±4.91°， 34.8°±8.15°， 33.9°±4.72°， 41.3°±5.32°， 43.5°±4.25°， 3.13±0.24 mm， 1.45±0.22 mm， 1.36±0.28 mm， 0.93±0.20 mm， and 0.96±0.21 mm， respectively. The differences between the anterior chamber volume and the central and peripheral anterior chamber depths were statistically significant （Z=-5.466， -7.352， -2.614， -2.546， -2.203， -3.327， P<0.05）. Conclusion  The anterior chamber volume and the central and peripheral anterior chamber depths decreased soon after LASIK was performed with the Allegro Oculyzer system. The change in the central anterior chamber depth was greater than that of the peripheral anterior chamber depth.