The location of BBO crystal in the cavity effecting the output energy in the intracavity frequency-doubling of a flashlamp-pumped Cr:LiSAF laser is researched.The benefit net phase shift due to dispersion between the fundamental and the harmonic wave beam in the air path between BBO crystal and the mirror M3 is a multiple of 2π. If the net phase shift ofπ/4 is allowed, this requires a BBO crystal movement of no more than 9.4 mm at the fundamental wave of 900 nm and the harmonic wave of 450 nm.