Abstract: In view of lightening and strength reliability, a method of reliability calculation is proposed on the basis of grey relation analysis and in situ force data and implemented by way of VB program. Analyzes the harsh conditions and inaccurate results of conventional calculation methods for stress tests and evaluation. Discusses how to calculate the standard difference in grey relation analysis and reliability of normal distribution and how to transform equivalently other distributions to normal distribution. In conclusion, the method proposed is available to get rid of the harsh conditions for calculation and make the results more accurate. Moreover, it can be used to transform the logarithmic normal distribution into equivalent one.