The experiments for 2D triangulation ranging accuracy show that,under large visual angle condition,the 2D triangulation ranging error is obviously increased. Applying the pinhole imaging instead of normal lens imaging,the large visual angle abaxial light aberration of lens is demonstrated to be the main reason for the ranging error,and an empirical remedy equation is proposed,which can obviously improve ranging accuracy and speed. The experiment results show that,in the 50 mm×50 mm work region corresponding to the visualangle as large as 80°,the average ranging error in x and y direction is better than 2 mm,the average resolutions in x and y direction are 0.2 mm and 0.1 mm respectively.