To inspect and evaluate free-form surface(FFS) parts rapidly and precisely, the sampling strategies involved in inspecting processing were researched. Three kinds of sampling methods ,randomized Hamersley sampling, simple random sampling and aligned systematic sampling were proposed to specify a set of measuring points and a quasi particle swarm optimization searching was used to optimize the transformation parameters to implement the localization between measured FFS and designed FFS. Then , the surface subdivision method was taken to find the closest points on the design model corresponding to measured points to calculate the profile errors of the FFS. In order to compare the results of different sampling strategies, design models for parts were generated by non-uniform rational basis spline and some parts were manufactured on different machining centers to obtain the surfaces of different roughnesses based on the same processing technology. Finally,these parts were measured on a Coordinate Measuring Machine(CMM) by setting different sampling strategies and the profile errors were calculated by the proposed method and CMMs software, respectively. The experiments results verify that the best sampling strategy for FFS inspection is the randomized Hamersley sampling method and a medium size. It has the merits of higher precision, lower cost and less time. Moreover, the evaluation precision of FFS profile error computed by the proposed method is higher 10%-22% than that by CMM software. These results show that the proposed method is suitable for the profile error inspection of FFS parts rapidly and precisely.