Diesel particulate filter (DPF) clogging and high temperature failures are predominant issues affecting the reliability of diesel engines in the market applications. These failures, which include substrate crack and melting, can lead to a significant increment of tailpipe particulate matter (PM) emissions, even exceeding the acceptable limits. Such DPF events not only diminish the vehicle productivity but also escalate the maintenance costs. The DPF, situated downstream in the diesel engine exhaust system, is directly influenced by the health state of the upstream engine and diesel oxidation catalyst (DOC). Addressing the risks of DPF system failures is a complex systems engineering challenge. This paper employs a fault tree analysis (FTA) to identify the root causes of these failures, considering the DPF after-treatment functions, all elements affecting system performance, and key interconnections among these elements. Then the DPF reliability optimization strategies are discussed from a system optimization perspective, focusing on reducing the engine-out PM, ensuring the appropriate substrate volume and precious metal coating content for DPF clogging, improving the virtual DPF soot loading sensor accuracy, lowering the extremely uneven flow or DPF soot loading and adopting the conservative regeneration control for high temperature failures. These measures are crucial to mitigate the failure risks and ensure the reliable DPF operation. To achieve the tighter PN requirement of future regulation, additional DPF optimizations would be required. Adopting the new Cordierite material with a higher porosity, further smaller mean pore size and uniform pore size distribution are one of current developing tendencies from existing studies. The Cordierite material with membrane design would be a new developing direction for further improving of filtration efficiency and better hysteresis of DPF pressure drop, plus lower porosity and thicker wall design would get better robustness and DPF pressure drop.