The invention relates to a heat treatment process for a microalloyed steel wire. The process comprises the following steps that (1) the main alloy elements of the microalloyed steel wire comprise 0.8-0.82% of C, 0.17-0.3% of Si, 0.6-0.9% of Mn, 0-0.01% of P, 0-0.01% of S, 0.1-0.2% of Cr, 0.005-0.01% of Ni, 0.005-0.01% of Cu and 0.005-0.01% of Al, and (2) according to the heat treatment technological parameters, the microalloyed steel wire with the diameter being 3-8 mm is heated to 910-920 DEG C at the average heating rate of 2-18 DEG C per second and is subjected to heat preservation for 30-85 seconds so as to be austenitized rapidly, and then the steel wire is placed into a lead bath within the sorbite temperature range, is subjected to isothermal holding for 20-60 seconds, then is taken out and cools naturally. Compared with the prior art, the heat treatment process has the beneficial effects that by means of the heat treatment process, the problems existing in heat treatment of the microalloyed steel wire after microalloy is added into high-carbon steel are solved, the requirement for the grain size after austenitic transformation can be met, organizational preparation is made for subsequent machining of the steel sire, and the high-strength and high-tenacity steel wire is produced finally.