Due to the repeated disturbance to the rock pillars of urban parallel tunnels with small net spacing imposed by blasting construction, the mechanical behavior of the rock pillars is very complex and the rock pillars are subjected to destruction and destabilization. Taking the smallspacing tunnel in Xiameng University as project case, the author, with the aim to protect the rock pillars, expatiates on the construction technology for urban parallel tunnels with changing small spacing in terms of blasting parameters and reinforcement of the rock pillars.