The invention provides a sheet-like object posture adjusting method. The method includes the following steps that a sheet-like object picking device is used for picking up sheet-like objects from a sheet-like object pile; a first conveying device pushes the sheet-like object picking device to move so as to convey the sheet-like objects along a first conveying path; when the first conveying device starts to push the sheet-like object picking device to move, a counting device starts counting; when all first detection marks on the sheet-like objects pass through corresponding first detection units, the counting device stops counting and transmits multiple first counting values corresponding to the first detection marks to a control device; and the control device controls the first conveying device, so that posture adjustment of the sheet-like objects is completed when the sheet-like objects reach a first conveying terminal. According to the sheet-like object posture adjusting method provided by the invention, the sheet-like objects can be aligned precisely and efficiently in the sheet-like object conveying process, and therefore the sheet-like objects can be aligned with target positions when reaching the terminal so that operation of the next procedure can be conveniently conducted.