The current HPR1000 has a high construction cost and weak economic competitiveness due to its complex system and large containment. This study proposes a conceptual design of an advanced containment system based on HPR1000, which aims at reducing the construction cost of nuclear power plants without reducing their safety. In the design, the In-containment Refueling Water Storage Tank (IRWST) and spray system were discarded, and the space of the double containment vessel was used to create an annular cavity pool (ACP). The transient pressurization in the containment caused in the early stages of the accident can be quickly suppressed by ACP instead of the traditional large-volume suppression concept. And due to the significant condensation of steam within the ACP water, the transportation of air into the ACP results in a reduction in the air mass fraction in the vicinity of the passive containment heat removal system (PCHR) located within the containment structure. This phenomenon subsequently leads to an enhancement in heat transfer performance. In addition, ACP also serves as the water source for the safety injection system, the reactor cavity water injection system, and the core replacement system. Compared with HPR1000, the system of the preliminary design has been greatly simplified, and the size of the containment vessel has been reduced by nearly 47%. The simulation of the large-break loss-of-coolant accident (LBLOCA) scenario has been conducted to examine the response of the containment system, specifically focusing on the performance of the safety injection system and suppression system. The results show that the integrity of the containment and core was ensured throughout the accident, and there was a safety margin.