The electron beam local post-weld heat treatment (EBLPWHT) is a rather new method that provides the advantages ofhigh precision, flexibility and efficiency, energy saving and higher productivity. This paper studies the effect of two post-weldheat treatment processes on the microstructure, mechanical properties and fracture toughness of an electron beam weldedjoints in 30CrMnSiNi2A steel. EBLPWHT, in a vacuum chamber, immediately after welding and a traditional furnace wholepost-weld heat treatment (FWPWHT) were compared. The experimental results show that, after EBLPWHT treatment, themain microstructure of weld was changed from coarse acicular martensite into lath martensite, HAZ was changed from lathmartensite, bainite into lower bainite, and base metal was changed from ferrite and pearlite into upper bainite and residualaustenite. The microstructures of different zones of joints in FWPWHT condition were tempered sorbite. The properties ofwelded joints can be improved by the EBLPWHT in some extent, and especially largely for the fracture toughness of weldedjoints. However the value of fracture toughness of base metal is comparatively low, so appropriate heat treatment parametersshould be explored in the future.