Many reports have been shown about the strength design of glulam using simulation method, hi the simulation method one of the important problems is how to deal with correlations among strength factors like as modulus of elasticity (MOE). modulus of rapture (MOR), tensile strength (σT) and compression strength (σ c) For example in case that the MOR criteria of glulam is σ ni/ f ni + σ bi / f bi ≥ 1 - a correlation between f ni and f bi exists. Here σ ni and σ bi are the axial stress and the bending stress of i-th lamina respectively./, and are also the axial strength and the bending strength of i-th lamina respectively. How can we take this correlation into consideration in the calculation of the strength of glulam? And it is very difficult to measure the correlation coefficients among MOR. σ T andσ c-I developed the method by which these problems could be solved. And using random variables generated by this method, strengths of glulam were simulated. They were almost same as experimental values. This result indicated the usefulness of this method.