An electric chuck of a gear guide rod mechanism consists of a base, a rotating disc, a cross roller guide way, a connecting disc, a synchronous wheel, a rotating seat, a main gear I, a pinion gear I,an intermediate transmission gear I, linear guideways I, optical axis seats I, optical axes I, sliding blocks I, steel balls I, a motor I, an intermediate shaft I, bearings, retaining ring for bores,sliding block fixed shafts, a motor II, a pinion gear II, an intermediate transmission gear II, a main gear II, sliding blocks II, optical axes II, optical axis seats II, linear guideways II and steelballs II. The optical axes I and the optical axes II which are perpendicular mutually in the mechanism get close to or far away from the center so as to clamp a steel pipe.