A method for processing instant application messages is provided. The method is performed by a device and includes: receiving, by a modem of the device, an instant application message transmitted from an application server to an application processor of the device; determining, by the modem, whether the application processor is in a sleeping mode and the instant application message is an emergency message; and transmitting, by the modem, the instant application message to a co-processor of the device to cache the instant application message when the application processor is in the sleeping mode and the instant application message is not an emergency message.