The catenary geometric parameters are important factors that affect the safe operation of the railway. Among them, height of conductor and stagger value are two key parameters. At present, the two parameters are mainly measured by laser distance sensor and angle measuring device with manual aiming method, with low measuring speed and poor efficiency. In order to improve the speed and accuracy of catenary geometric parameters detection, a new automatic measuring method of contact wire’s parameters based on laser scanning and imaging is proposed. The DLT method is used to calibrate the parameters of the linear array CCD camera. The direction of the scanning laser beam and the spatial coordinate of the starting point of the beam are calculated by geometric method. Finally, the equation is established using the calibrated parameters and the imaginary coordinates of the imaging point, to solve the spatial coordinate of the measured point on the contact wire, so as to calculate height of conductor and stagger value. Different from the traditional hand-held laser phase measuring method, the new method can achieve measurement of the catenary geometric parameters automatically without manual aiming. Through measurement results, accuracy can reach 2mm.