A remote server, a remote control system and a remote control method are provided. The remote server includes a connector and a processor. The connector is connected to a KVM switch. The KVM switch is connected to at least two machines. The connector receives a plurality of screen images of the machines through the KVM switch, wherein the screen images are respectively captured at the machines. The processor generates a plurality of control instructions according to the screen images, respectively. The control instructions are transmitted from the connector to the machines through the KVM switch, respectively.