A method for sending a message, wherein the method comprises: detecting (101, 201) whether a user is located in a target place; if the user is not located in the target place, detecting whether a door or a window of the target place is open; and if a door or a window of the target place is open, sending (103, 205) a prompt message to a device carried by the user, wherein detecting whether a user is located in a target place comprises: receiving a second message sent from the device carried by the user, and detecting whether the user is located in the target place based on the second message and a pre-stored message corresponding to the target place, the second message indicating a location of the user and the pre-stored message indicating a location of the target place, characterised in that the method further comprises: detecting whether the user is located in the target place based on the second message and a pre-stored message corresponding to the target place, wherein the second message is a first device list and the pre-stored message is a second device list, detecting whether the user is located in the target place based on similarity between the first device list and the second device list, the first device list being a list of devices which are connected in a first network covering a place where the user is currently located, and the second device list being a list of devices which are connected in a second network covering the target place. detecting (101, 201) whether a user is located in a target place; if the user is not located in the target place, detecting whether a door or a window of the target place is open; and if a door or a window of the target place is open, sending (103, 205) a prompt message to a device carried by the user, wherein detecting whether a user is located in a target place comprises: receiving a second message sent from the device carried by the user, and detecting whether the user is located in the target place based on the second message and a pre-stored message corresponding to the target place, the second message indicating a location of the user and the pre-stored message indicating a location of the target place, characterised in that the method further comprises: detecting whether the user is located in the target place based on the second message and a pre-stored message corresponding to the target place, wherein the second message is a first device list and the pre-stored message is a second device list, detecting whether the user is located in the target place based on similarity between the first device list and the second device list, the first device list being a list of devices which are connected in a first network covering a place where the user is currently located, and the second device list being a list of devices which are connected in a second network covering the target place. receiving a second message sent from the device carried by the user, and detecting whether the user is located in the target place based on the second message and a pre-stored message corresponding to the target place, the second message indicating a location of the user and the pre-stored message indicating a location of the target place, characterised in that the method further comprises: detecting whether the user is located in the target place based on the second message and a pre-stored message corresponding to the target place, wherein the second message is a first device list and the pre-stored message is a second device list, detecting whether the user is located in the target place based on similarity between the first device list and the second device list, the first device list being a list of devices which are connected in a first network covering a place where the user is currently located, and the second device list being a list of devices which are connected in a second network covering the target place. detecting whether the user is located in the target place based on the second message and a pre-stored message corresponding to the target place, wherein the second message is a first device list and the pre-stored message is a second device list, detecting whether the user is located in the target place based on similarity between the first device list and the second device list, the first device list being a list of devices which are connected in a first network covering a place where the user is currently located, and the second device list being a list of devices which are connected in a second network covering the target place.