The relationship of effective index and ridge height under different ridge width, core height and the short side width of the core plate were systematically studied in effective index method with organic polymer asymmetric ridge waveguide as the object. The result shows that both the structures of ridge waveguide had the same characteristics. They were the effective index increased with increasing of ridge height, ridge width when core height was constant and with increasing of core height when the ridge height, ridge width were constant. For the asymmetrical ridge waveguide, the effective index decreased with reduction of the short side width of the core plate when other conditions were constant. The result is valuable for reference in terms of application of the organic polymer asymmetric ridge waveguide.