An incoming call processing method configured for a handheld electronic apparatus having a touch display screen, the incoming call processing method comprising: receiving an incoming call; deciding whether to display a sub-call window interface on an operating interface displayed on the touch display screen by determining whether the operating interface is a normal application operating interface, wherein the normal application operating interface includes any operating interface other than a full-screen call interface, a screen-locking interface and a standby interface; if the operating interface is not the normal application operating interface, displaying the full-screen call interface on the touch display screen to replace the operating interface originally displayed on the touch display screen; if the operating interface is the normal application operating interface, further determining whether the handheld electronic apparatus is preset to display the sub-call window interface; if the handheld electronic apparatus is not preset to display the sub-call window interface, displaying the full-screen call interface on the touch display screen to replace the operating interface originally displayed on the touch display screen; and if the handheld electronic apparatus is preset to display the sub-call window interface, displaying the sub-call window interface on the operating interface without blocking the entire operating interface and without suspending the current task performed by a user, wherein the sub-call window interface at least comprises a call interface switching control key for switching between the sub-call window interface and the full-screen call interface and a sub-call window zooming control key for hiding the sub-call window interface to prevent the sub-call window interface from blocking the operating interface displayed on the touch display screen. receiving an incoming call; deciding whether to display a sub-call window interface on an operating interface displayed on the touch display screen by determining whether the operating interface is a normal application operating interface, wherein the normal application operating interface includes any operating interface other than a full-screen call interface, a screen-locking interface and a standby interface; if the operating interface is not the normal application operating interface, displaying the full-screen call interface on the touch display screen to replace the operating interface originally displayed on the touch display screen; if the operating interface is the normal application operating interface, further determining whether the handheld electronic apparatus is preset to display the sub-call window interface; if the handheld electronic apparatus is not preset to display the sub-call window interface, displaying the full-screen call interface on the touch display screen to replace the operating interface originally displayed on the touch display screen; and if the handheld electronic apparatus is preset to display the sub-call window interface, displaying the sub-call window interface on the operating interface without blocking the entire operating interface and without suspending the current task performed by a user, wherein the sub-call window interface at least comprises a call interface switching control key for switching between the sub-call window interface and the full-screen call interface and a sub-call window zooming control key for hiding the sub-call window interface to prevent the sub-call window interface from blocking the operating interface displayed on the touch display screen.