The goal of this research is to develop a systematic, accurate and robust method for printed circuit board (PCB) positioning evaluation in the testing fixture. Theoretical analysis and experimental observation of tolerance distribution in bed-of-nails fixture were involved. Actual deformation of PCB (translation, rotation and deflection) could be obtained based upon a proposed model. The combined accuracy of the test lands positioning (false failure rate) were estimated by the Weibull distribution. All data processing was finished by MATLAB. Results will be helpful for evaluation of the minimal size of the PCB test lands and modification of the testing fixtures.