The invention relates to a natural gas measuring instrument based on the internet of things. The instrument comprises a main body, a connecting pipe, a card reading mechanism and a central control mechanism, wherein the card reading mechanism comprises a card reader and a locking mechanism; the locking mechanism comprises a locking frame, a locking component and an unlocking component; a locking unit comprises a spring, a push plate, a push rod, a locking door frame and a hinge pin; the unlocking unit comprises an operation block, a first connecting rod and a second connecting rod; and a working power module comprises a working power circuit. In the natural gas measuring instrument based on the internet of things, a radio frequency card can be preserved reliably and hermetically by the locking mechanism; meanwhile, by the unlocking component, flexible unlocking of the radio frequency card is realized, so that the practicability of a detecting instrument is improved; moreover, in the working power circuit, the stable output of supply voltage can be realized through the feedback collection of input voltage and output voltage, which is performed by the integrated circuit; and the working stability and reliability of the detecting instrument is improved.