A study of integration for different sensing functions is described. Three different noncontact measuring functions, including a micrometer, a roughness meter, and a profilometer, are integrated into one new sensor. In this sensor, one common laser source, optical system, and photodetector are shared. Based on the theory of laser scattering and interferometry, this sensor can be used to measure the surface roughness and microprofile with the measurement range of Ra = 0.001 to 3 μm. Based on the theory of triangulation this sensor can be used to measure the microdisplacement with a measurement range of 0.5 to 300 μm. The accuracies of this sensor are similar to each existing single sensor for the same function. A typical application of this sensor is to complete the measurements of the diameter, surface quality, and form error of a cylinder or cannon in operation. This integrated sensor is applicable to design a virtual instrument with multiple functions.