The appearance design of precision parts has strict requirements on the dimensional accuracy. In order to reduce the scale deviation and meet the performance index, the appearance design of complex surface precision parts based on multi laser sensor detection is proposed. The tilt angle between the sensor and the imaging axis is determined, and the internal information of the part is collected; The fuzzy set theory and membership function are introduced to smooth the collected data and reduce the noise. The coupling relationship among geometric, physical and performance parameters is established, and the geometric parameters are compensated by linear sensitivity model. Three kinds of surfaces and four frame systems are defined to express the pose relationship between constraint conditions, which are transformed into matrix form to obtain deeper pose expression, so as to detect whether the appearance of precision parts is reasonable and whether the parts are more practical. Experimental results show that this method can obtain the information of the parts comprehensively and reduce the data noise. Detection can meet the requirements of the appearance design of precision parts and make the appearance of the designed parts more accurate, which is conducive to the actual use of precision parts.