A printing system comprising: a printing unit that performs printing on a sheet; a conveyance mechanism that has a printing path for guiding a sheet to a printing position of the printing unit and a reverse path for reversing the sheet passing through the printing position and guiding the sheet again to the printing position; a control unit that performs double-side printing processing depending on a plurality of methods in which maximum numbers of the sheets existing in the conveyance mechanism at the same time are different from each other, the plurality of methods comprising a first method and a second method, wherein the maximum number of the sheets existing in the conveyance mechanism at the same time is larger in the first method than in the second method; a detection unit that detects a sheet jamming; and a determination unit that determines a probability of sheet jamming occurring in the conveyance mechanism based on a detection result by the detection unit, characterized in that when the determination unit determines that the jamming occurrence probability is equal to or lower than an upper limit, the control unit selects the first method, and when the determination unit determines that the jamming occurrence probability is higher than the upper limit, if a relative difference in an individual jamming occurrence probability between the first method and the second method is higher than a reference value, the control unit selects the second method, and if the relative difference is equal to or smaller than the reference value, the control unit selects the first method, wherein the individual jamming occurrence probability refers to a occurrence probability of jamming which occurs in the printing system, when the double-side printing processing is performed using each of the plurality of methods, and control unit performs the double-side printing processing in accordance with the selected method. a printing unit that performs printing on a sheet; a conveyance mechanism that has a printing path for guiding a sheet to a printing position of the printing unit and a reverse path for reversing the sheet passing through the printing position and guiding the sheet again to the printing position; a control unit that performs double-side printing processing depending on a plurality of methods in which maximum numbers of the sheets existing in the conveyance mechanism at the same time are different from each other, the plurality of methods comprising a first method and a second method, wherein the maximum number of the sheets existing in the conveyance mechanism at the same time is larger in the first method than in the second method; a detection unit that detects a sheet jamming; and a determination unit that determines a probability of sheet jamming occurring in the conveyance mechanism based on a detection result by the detection unit, characterized in that when the determination unit determines that the jamming occurrence probability is equal to or lower than an upper limit, the control unit selects the first method, and when the determination unit determines that the jamming occurrence probability is higher than the upper limit, if a relative difference in an individual jamming occurrence probability between the first method and the second method is higher than a reference value, the control unit selects the second method, and if the relative difference is equal to or smaller than the reference value, the control unit selects the first method, wherein the individual jamming occurrence probability refers to a occurrence probability of jamming which occurs in the printing system, when the double-side printing processing is performed using each of the plurality of methods, and control unit performs the double-side printing processing in accordance with the selected method.