Friction sensors are three-dimensional MEMS sensors specifically designed for measuring the surface friction of hypersonic vehicle models. In order to realize its reliable assembly， a MEMS friction sensor micro assembly system is designed， including a double micro vision system， high-precision fixture design， precision operation tools， precision positioning platform， high-precision visual recognition algorithm， and dispensing process. First， an analysis of the system reveals that the influence on the performance of the sensor is related to the geometric tolerance of the floating rod and chip assembly of the sensor， the concentricity between the upper circular surface of the floating rod and the circular hole of the upper cover of the sensor after the assembly， and the flush of the end face is related to the height difference. Then， according to the influencing factors， a high-precision fixture is designed to ensure that the geometric tolerance of each component of the sensor before assembly is within the theoretical range. Moreover， a precision operation tool is designed to ensure the accurate absorption of components and the stability of handling components in the assembly process， the shaft hole position of the positioning assembly is accurately identified using double micro vision， and the precision positioning platform is driven to transport each component to the corresponding assembly position. Finally， the influence of the dispensing process on the performance of the sensor assembly is investigated. The experimental results reveal that following the sensor assembly， the average concentricity deviation between the floating head and the circular hole of the upper end cover is 4.90 μm. The runout value of the height difference between the floating head and the end face of the upper end cap is 1 μm. The friction sensor micro-assembly system fully meets the requirements of the friction sensor assembly.