A method of text script generation for a corpus-based text-to-speech system includes searching in a source corpus having L sentences, selecting N sentences with a best integrated efficiency as N best cases, and setting iteration k to be 1; for each case n of the N best cases, selecting Mk+1 best sentences with the best integrated efficiency from the unselected sentences in the source corpus; keeping N best cases out of the total unselected sentences for next iteration, and increasing iteration k by 1; and if a termination criterion being reached, setting the best case in the N traced cases as the text script, otherwise, returning to the (k+1)th iteration of searching in the unselected sentences for (k+1)th sentence; wherein the best integrated efficiency depends on a function of combining the covering rate of the synthesis unit type, the hit rate of the synthesis unit type, and the text script size.