Proposed in this paper is a variable- step corner detection algorithm for the laser binocular vision detec-tion of fillet weld position of the T- type joint between corrugated plate and box girder.In this algorithm,a binocularvision detection model of fillet weld position is established and an image preprocessing is performed for the laserstripe images according to the imaging characteristics of the stripe projected on the fillet weld.Then,a variable-step searching algorithm is developed to find the near- corner point in the laser stripe,and several pixels at bothsides of the near- corner point are selected to construct two straight lines.Finally,the corner point of the fillet weldis determined according to the intersection point of the two constructed lines.Experimental results show that theproposed algorithm is superior to those traditional ones due to its high reliability,low detection error (less than0. 1mm) and low 3D trajectory reconstruction error of fillet weld (less than 1mm).