The invention provides a testing method of researching influence of a surrounding rod cluster to single bars in spent fuel assembly spraying and cooling. By means of the method, a comprehensive test research on the influence of the surrounding rod cluster to single bars in spent fuel assembly spraying and cooling can be conducted, and the method is used for judging whether support of 5*5 rod cluster represents a true 17*17 type spent fuel assembly spraying and cooling effect, thereby laying a foundation for follow-up further deep researches.