A method to operate an infrared camera by a user wherein the camera comprises: a photosensitive element, the spectrum sensing range of the photosensitive element including visible and infrared spectrum; a flash light source, the flash light source uses gas discharge flash; a first optical filter, removably covering the emitted light path of the flash light source, the first optical filter being configured to filter out visible lights and allow infrared light to transmit; a second optical filter, removably disposed in the incident light path of the photosensitive element, the second optical filter being configured to filter out infrared light and allow visible lights to transmit; a processing module, used to execute steps comprising: executing working flow, the working flow including a photographing flow, executing the photographing flow, the photographing flow including controlling the flash light source to flash and acquiring photo data collected by the photosensitive element; wherein the photographing flow further includes: executing a flash working mode setting flow, the flash working mode setting flow including: acquiring input flash setting signal and setting the flash working mode to infrared mode or non infrared mode based on the flash setting signal: and the photographing flow further includes processing the photo data, when the flash working mode is set to infrared mode, using a predefined black and white processing mode to process the photo data, when the flash working mode is set to non infrared mode, using a predefined colour processing mode to process the photo data; characterized in that the flash working mode is set to infrared mode, the user mounts the first optical filter to cover the emitted light path of the flash light source, and removes the second optical filter from the light path of the photosensitive element, and if the flash working mode is set to non infrared mode, the user removes the first optical filter from the emitted light path of the flash light source and disposes the second optical filter in the incident light path of the photosensitive element. a photosensitive element, the spectrum sensing range of the photosensitive element including visible and infrared spectrum; a flash light source, the flash light source uses gas discharge flash; a first optical filter, removably covering the emitted light path of the flash light source, the first optical filter being configured to filter out visible lights and allow infrared light to transmit; a second optical filter, removably disposed in the incident light path of the photosensitive element, the second optical filter being configured to filter out infrared light and allow visible lights to transmit; a processing module, used to execute steps comprising: executing working flow, the working flow including a photographing flow, executing the photographing flow, the photographing flow including controlling the flash light source to flash and acquiring photo data collected by the photosensitive element; wherein the photographing flow further includes: executing a flash working mode setting flow, the flash working mode setting flow including: acquiring input flash setting signal and setting the flash working mode to infrared mode or non infrared mode based on the flash setting signal: and the photographing flow further includes processing the photo data, when the flash working mode is set to infrared mode, using a predefined black and white processing mode to process the photo data, when the flash working mode is set to non infrared mode, using a predefined colour processing mode to process the photo data; executing working flow, the working flow including a photographing flow, executing the photographing flow, the photographing flow including controlling the flash light source to flash and acquiring photo data collected by the photosensitive element; wherein the photographing flow further includes: executing a flash working mode setting flow, the flash working mode setting flow including: acquiring input flash setting signal and setting the flash working mode to infrared mode or non infrared mode based on the flash setting signal: and the photographing flow further includes processing the photo data, when the flash working mode is set to infrared mode, using a predefined black and white processing mode to process the photo data, when the flash working mode is set to non infrared mode, using a predefined colour processing mode to process the photo data; acquiring input flash setting signal and setting the flash working mode to infrared mode or non infrared mode based on the flash setting signal: and the photographing flow further includes processing the photo data, when the flash working mode is set to infrared mode, using a predefined black and white processing mode to process the photo data, when the flash working mode is set to non infrared mode, using a predefined colour processing mode to process the photo data;