Software testing sufficiency means that the software�s performance on limited testing data can represent its performance on all input data. Ideally, in software testing, the testing should be carried on till all errors in the program are detected and removed. As a testing strategy to measure the completeness of the test cases set, mutation testing is a defects-oriented unit testing technology, and a feasible software testing method to generate a complete set of test cases. The article systematically simulates the different defects in software by using mutation operators to create mutants, and then construct testing data set to be able to kill these mutants. It analyzes the procedures of mutation testing and the generation of mutation operators with specific examples. Experiment indicates that the program mutation technology has enhanced the test cases, which greatly improved the software testing sufficiency.