Objective: To test the validity of GNTI used in underachievement children. Methods: 41 underachievement children were tested with GTNI and C-WISC concurrently,and their results were compared. Results: ①The correlation coefficients between the total score of GTNI and the FIQ,VIQ AND PIQ of C-WISC were 0.57,0.45,0.44,respectively; The scores of sorting and reasoning subtest of GTNI significantly correlated with VIQ of C-WISC, and the score of number-colour read of GTNI significantly correlated with VIQ of C-WISC. ②The total score of GTNI was higher than the FIQ of C-WISC, and the score of picture completion and sorting subtest of GTNI were higher than those of C-WISC. Conclusion: GTNI is useful for the special group of the underachievement children in testing intelligence in accordance with principle of cultural justice.