This article specifically recommends the great significance of building homeland security response system so as to set up the security net by all-hazards approach. The main idea of this article is to strengthen collaboration and preparedness of all the systems or response mechanisms. First, I discuss five 'emergency response' key systems such as disaster prevention, nuclear accidents, anti-terrorism, and biological pathogens, and toxic chemical substances, etc. so as to evaluate or propose relevant suggestions. Secondly, in order to practice on national overall response mechanism-the practice of single response mechanism, we shall focus on the goal of preparing for emergency response system, building homeland security operation mechanisms; and integrating all the response plans from varied emergency systems. Thus, according to international experiences, Taiwan must improve and set up a dedicated unit capable of coordination and integration within the Yuan's authority level. I suggest the ways to coordinate and integrate all the homeland security response systems by developmental trends of homeland security. It is highly necessary and urgent to build this homeland security net by all-hazards approach.