Recently, bulk nanobubbles have attracted intensive attention due to the unique physicochemical properties and important potential applications in various fields. In this study, periodic pressure change was introduced to generate bulk nanobubbles. N₂ nanobubbles with bimodal distribution and excellent stabilization were fabricated in nitrogen-saturated water solution. O₂ and CO₂ nanobubbles have also been created using this method and both have good stability. The influence of the action time of periodic pressure change on the generated N₂ nanobubbles size was studied. It was interestingly found that, the size of the formed nanobubbles decreases with the increase of action time under constant frequency, which could be explained by the difference in the shrinkage and growth rate under different pressure conditions, thereby size-adjustable nanobubbles can be formed by regulating operating time. This study might provide valuable methodology for further investigations about properties and performances of bulk nanobubbles.