The invention relates to a metal sheet longitudinal and transverse shearing device, in particular to a tinplate longitudinal and transverse shearing device having longitudinal and transverse shearing switching. The tinplate longitudinal and transverse shearing device comprises a longitudinal shearing circular shear and a transverse shearing circular shear, wherein the longitudinal shearing circular shear is provided with a positioning conveying belt moving longitudinally by connection; the positioning conveying belt is provided with a compression wheel; the rear end of the positioning conveying belt is provided with a transverse shearing conveying platform by connection; two abreast primary conveying belts moving transversely are arranged on the transverse shearing conveying platform; lifting devices for making the primary conveying belts move up and down are arranged on the primary conveying belts; the rear ends of the primary conveying belts are provided with two abreast secondary conveying belts having a moving speed higher than that of the primary conveying belt by linking; a positioning push pawl moving to and fro is arranged outside the two secondary conveying belts respectively; and the rear end of the positioning push pawl is provided with the transverse shearing circular shear. The device solves the problems of malposition, lamination, large noise and the like of strips in the tinplate longitudinal and transverse shearing switching processes, increases the speed of the tinplate longitudinal and transverse production line and has the characteristics of simple structure and convenient implementation.