A projection apparatus maintenance system, comprising: a projection apparatus, comprising a first processor, a first communication interface and a projection unit, wherein the first processor is coupled to the first communication interface and the projection unit, and the projection unit projects a projection image according to an image data; and a mobile apparatus, comprising a second processor and a second communication interface, wherein the second processor is coupled to the second communication interface, wherein the mobile apparatus has installed an application program, and the mobile apparatus interacts with the projection apparatus by activating the application program; characterized in that when the projection apparatus is connected to the mobile apparatus, the projection apparatus transmits usage data corresponding to the projection apparatus through the first communication interface to the mobile apparatus, and the mobile apparatus receives the usage data from the projection apparatus through the second communication interface; the mobile apparatus receives maintenance data corresponding to the projection apparatus from a network server through the second communication interface; the mobile apparatus further comprises a sensing component coupled to the second processor and the sensing component is configured to sense an environmental information, wherein the environmental information includes at least one of sensed ambient temperature, ambient humidity, ambient brightness, mobile apparatus shaking, mobile apparatus tilt angle, mobile apparatus acceleration, ambient pressure, and captured external images; the application program of the mobile apparatus controls the second processor to generate at least one maintenance command according to the environmental information sensed by the sensing component and according to at least one of the usage data and the maintenance data and to transmit the at least one maintenance command through the second communication interface; the projection apparatus receives the at least one maintenance command through the first communication interface, and the first processor of the projection apparatus executes a maintenance operation corresponding to the projection apparatus based on the at least one maintenance command; wherein the at least one maintenance command comprises a system update command; and wherein the maintenance operation executed by the first processor of the projection apparatus comprises a system update operation of the projection apparatus. a projection apparatus, comprising a first processor, a first communication interface and a projection unit, wherein the first processor is coupled to the first communication interface and the projection unit, and the projection unit projects a projection image according to an image data; and a mobile apparatus, comprising a second processor and a second communication interface, wherein the second processor is coupled to the second communication interface, wherein the mobile apparatus has installed an application program, and the mobile apparatus interacts with the projection apparatus by activating the application program; characterized in that when the projection apparatus is connected to the mobile apparatus, the projection apparatus transmits usage data corresponding to the projection apparatus through the first communication interface to the mobile apparatus, and the mobile apparatus receives the usage data from the projection apparatus through the second communication interface; the mobile apparatus receives maintenance data corresponding to the projection apparatus from a network server through the second communication interface; the mobile apparatus further comprises a sensing component coupled to the second processor and the sensing component is configured to sense an environmental information, wherein the environmental information includes at least one of sensed ambient temperature, ambient humidity, ambient brightness, mobile apparatus shaking, mobile apparatus tilt angle, mobile apparatus acceleration, ambient pressure, and captured external images; the application program of the mobile apparatus controls the second processor to generate at least one maintenance command according to the environmental information sensed by the sensing component and according to at least one of the usage data and the maintenance data and to transmit the at least one maintenance command through the second communication interface; the projection apparatus receives the at least one maintenance command through the first communication interface, and the first processor of the projection apparatus executes a maintenance operation corresponding to the projection apparatus based on the at least one maintenance command; wherein the at least one maintenance command comprises a system update command; and wherein the maintenance operation executed by the first processor of the projection apparatus comprises a system update operation of the projection apparatus.