There exist, some shortcomings in the conventional method of evaluating the internal bond strength of particleboards. For one thing, it takes too much time to opportunely control the manufacturing process of the particleboard. After close observation and studying the character of the cross section of the particleboard under X-ray, we devised a direct ditching method, which has been proved to be convenient and practicable, only the specimen for test should not be too large lest it split.