Pressurizer bubble collapse is a critical operation that must be completed during the outage of nuclear power unit. HUALONG-1 nuclear power station fully draws on the advanced design concept and engineering construction and operation experience of the third-generation nuclear power technology. However, according to the current design requirements, the operation of pressurizer bubble collapse is carried out at the 90 °C temperature platform of the primary loop, which becomes the critical path of the outage. Based on the analysis of the control principle of primary cooling and depressurization and the pressurizer bubble collapse, optimization schemes are provided in this article. Rise the pressurizer liquid level before residual heat removal system is connected to primary loop. Furthermore, the primary loop simultaneously cooling and depressurization during the process of pressurizer bubble collapse. Then, the feasibility of the scheme is simulated by validation platform. The critical path time of outage can be greatly saved by the optimization scheme. And the problem of pressurizer cold shock caused by reverse flow will be avoided. Therefore, the operation economy and equipment reliability of unit are improved by the optimization scheme.