Embodiments of the invention provide a program defect detection method and device. The method comprises the steps of obtaining potential defects of a to-be-detected program; obtaining a first assertion expression according to the defect type and the defect position of the potential defect, and inserting the first assertion expression into a corresponding position of the to-be-detected program to obtain a second assertion expression; and verifying the second assertion expression, and if a verification result meets a preset condition, judging and knowing that the potential defect is a real program defect. According to the embodiment of the invention, the assertion expression is inserted into the corresponding position of the to-be-detected program according to the defect type and defect position of the potential defect in the to-be-detected program, so that the real program defect in the to-be-detected program is determined more quickly, and the defect positioning accuracy is improved.