The invention provides a clamp ammeter based on a Rogowski coil. The ammeter comprises a shell, a detection jaw, a circuit board and a battery, wherein the detection jaw is electrically connected with the circuit board, a display screen is arranged on the shell, and the display screen is electrically connected with the circuit board. The ammeter further comprises a Rogowski coil electrically connected with the circuit board, a selector switch is arranged on the side wall of the shell and electrically connected with the circuit board, and the selector switch is provided with a first gear and a second gear. When the selector switch is switched to the first gear, the detection jaw works, and when the selector switch is switched to the second gear, the Rogowski coil works, so that the detection jaw and the Rogowski coil of the clamp ammeter can work independently, namely the clamp ammeter has two detection functions, and the multifunction of the clamp ammeter is greatly improved; and when the condition that is not suitable for detecting the detection jaw is met, the Rogowski coil can be used for detecting and measuring, so that the detection convenience of the clamp ammeter and the maintenance convenience of maintenance personnel can be well improved.