In　this　paper,　a　novel　space-time　generalized　finite　difference　method　(GFDM)　is　proposed　for　solving　transient　heat　conduction　problems　by　integrating　a　direct　space-time　discretization　technique　into　the　meshless　GFDM.　The　spatial　and　temporal　dimensions　are　simultaneously　discretized　by　randomly　distributed　nodes　in　the　coupled　space-time　continuum.　Transient　heat　conduction　in　homogenous　and　heterogeneous　materials　are　analyzed　by　this　novel　meshless　space-time　GFDM.　Examples　involving　multidimensional　spatiotemporal　domains　and　various　complex　boundary　conditions　are　studied　and　discussed.　The　high　accuracy　and　efficiency　of　this　new　algorithm　are　verified　by　comparing　with　analytical　and　other　numerical　results.