The invention relates to the field of book binding, in particular to a novel book 
cutting positioning 
regulator mechanism in a three-surface book trimming 
machine. The novel book 
cutting positioning 
regulator mechanism in the three-surface book trimming 
machine comprises two oppositely arranged 
cutting positioning regulators; each cutting positioning 
regulator is provided with a 
servo power driver fixed on a rack; each 
servo power driver is connected with a first 
moving frame by a gear and a rack; each first 
moving frame is provided with first guide shafts, a control motor and a second 
moving frame; each control motor drives a screw rod by a nut; each screw rod is movably matched with the corresponding second moving frame; second guide shafts are arranged on each second moving frame in a movable penetrating mode; the 
tail ends of the second guide shafts of each 
servo power driver are fixed with a fixing part; positioning blocks are arranged on the fixing parts; the positioning blocks between the two cutting positioning regulators are opposite in positions. The novel book cutting positioning regulator mechanism in the three-surface book trimming 
machine is simple in structure and short in regulation time, and the positioning precision is improved.