A miniature gas detection and purification device is disclosed for a user to carry with himself, and includes a main body, a purification module, a gas guider and a gas detection module. The gas detection module detects gas of surrounding environment to obtain a gas detection datum, and controls the gas guider to be operated according to the gas detection datum, so that gas is inhaled into the main body and flows through the purification module for filtration and purification, and the gas purified is finally guided to a region close to the user.