As　an　additive　manufacturing　technology,　selective　laser　melting　(SLM)　can　form　any　complex　metal　parts,　which　has　unparalleled　advantages　compared　to　traditional　processing　methods.　However,　there　are　still　some　problems　such　as　accuracy　and　non-repeatability　to　overcome　to　apply　SLM　to　production　practice.　The　high-precision　monitoring　and　degradation　feedback　technology　of　SLM　equipment　is　the　future　development　direction.　The　real-time　monitoring　machine　can　repair　itself　and　avoid　the　tedious　detection　in　the　post-processing　stage.　The　researchers　mainly　monitor　the　quality　of　the　forming　process　by　molten　pool　signal,　temperature　signal,　sound　signal,　and　scanning　track.　The　forming　process　is　monitored　using　coaxial　detection　or　paraxial　detection　through　a　high-speed　camera,　pyrometer,　and　other　equipment.　This　paper　can　provide　theoretical　support　for　the　SLM　intelligent　monitoring　field.