In the present paper the authors report a research on testing the nonlinear optical performance of optical materials in visible and infrared band. Based on the second order nonlinear optic principle and the photoelectric signal detection technology, the authors have proposed a new testing scheme in which a infrared OPO laser and a method for separating the beams arising from frequency matching and the light produced by other optical effects were used. The OPO laser is adopted as light source to avoid the error of measurement caused by absorption because the double frequency signal of the material is in the transmittance band Our research work includes testing system composition, operational principle and experimental method. The experimental results of KTP, KDP, AGS tested by this method were presented. In the experiment several new infrared nonlinear materials were found. This method possesses the merits of good stability and reliability, high sensitivity, simple operation and good reproducibility, which can effectively make qualitative and semi-quantitative test for optical material's nonlinear optical properties from visible to infrared. This work provides an important test method for the research on second order nonlinear optical materials in visible, infrared and ultraviolet bands.