The invention provides a method and a system for determining one-dimensional barcode bar width compensation amount, and a barcode printing method. The invention belongs to the technical field of one-dimensional barcode. With the method and the system, a problem of excessive width during current one-dimensional barcode printing, or misidentification of the barcode, can be solved. The method for determining the one-dimensional barcode bar width compensation amount comprises the steps that: a module width and the width of a k-fold module width bar are determined; a test target of the k-fold module width bar is printed; through determining whether adjacent bars in the test target contact, a critical test target of the k-fold module width bar is found; and barcode bar width compensation amount is obtained according to the bar width of the critical test target. The one-dimensional barcode printing method provided by the invention comprises a step for determining the one-dimensional barcode bar width compensation amount with the method, and a step for printing according to the barcode bar width compensation amount. The system used for determining the one-dimensional barcode bar width compensation amount comprises a functional unit corresponding to the method. The method and the system provided by the invention can be used for printing 128-bit barcode and the like.