Abstract: A new multi-purpose onshore small modular reactor (SMR) named ACPR100, was proposed by China General Nuclear Power Group (CGN). The conceptual design of ACPR100 with integrated design, modular layout, passive safety, and multiple uses, etc., has been completed. The core physics analysis, sub-channel thermal-hydraulic analysis, coolant system analysis and typical accident analysis for ACPR100 were introduced in this paper. The results show that ACPR100 has many characteristics including high safety performance, good balance of the coolant system, and long refueling cycle conforming to the customer demand, etc.