Motor fuel composition and physical properties are closely related to the vehicular emissions controlling. Development of monitoring vehicle, integrating sulfur content detection device, vapor pressure testing device and fast simulation equipment for detergency detection, is benefit for random sample survey. Many efficient measures are taken to control influencing factors to ensure that portable devices can provide reliable testing results. The main influencing factors such as vehicle vibration, essential resource supply, environment conditions control and data quality control have been studied. Solution of vibration model is used for guiding the design and selection of vibration damping unit. Sufficient electricity and gas supply provide favorable operation condition for devices. And split-phase circuit, voltage regulator and filter device are set up for decrease electrical signal interference. Temperature and air circulation are strictly controlled to ensure a safe and comfortable environment. Additionally, keeping good repeatability of instruments and a proper analysis method of pre-treatment and pre-assessment are effective to reach credible results.