Abstract: Statistically analyzed are the present non-conformance data concerning the mechanical properties of the 12Cr1MoVG high-pressure boiler pipes as having been heat treated, which leads to identification of the operation difficulties related to the said heat treatment.Accordingly a heat treatment process of "intermittent quenching plus tempering" is proposed.It is also regarded via the analysis that the critical step for ensuring the good comprehensive mechanical performance of the said heavy-wall hi-pressure boiler pipe is properly controlling the after-normalization cooling speed to guarantee that the microstructure of the said pipe is mainly composed by ferrite+bainite.The result of relevant massive production demonstrates that thanks to the above mentioned heat treatment process, it is completely practical to produce the 12Cr1MoVG high-pressure boiler pipe as satisfactory to the applicable GB/T 5310-2017 specification and relevant customer requirements.