The upsetting parallel rebar splicing technology: Firstly, enlarging the rebar end by rebar upsetting machine. Secondly, threading on the enlarged end of rebar by rebar threading machine. Thirdly, connecting with an upsetting rebar coupler. After upsetting, the cross-sectional area will become larger and the strength of rebar end will become higher. After threading, the minimum thread diameter of rebar should not be less than the rebar base. Therefore, the splice can be as strong as the rebar base.