In line structured light vision measurement, extraction of the light-stripe center is an extremely important step. The existing extraction methods simply give out the stripe center position. Few take it into account how reliable of the extraction result is. In some special occasions, such as outdoor measurement, the reliability of the measurement results is greatly needed. Therefore, how to evaluate the reliability of the stripe center becomes a key problem. A reliability evaluation method for light-stripe-center extraction has been proposed, which is on the basis of the total energy of stripe cross section normalized by Gaussian model. Experimental results show that this method can effectively evaluate stripe center reliability in different situations, and the result is more consistent with practical need.