This is a research on orthogonal complementary codes, including complete complementary codes, super complementary codes, and generalized pairwise complementary code(GPC code). I discuss the properties of orthogonal complementary codes by the generation of orthogonal matries and realize its auto-correlation and cross-correlation are perfect. Apply orthogonal complementary codes on direct-sequence spreading system and offset stacked spreading system. In these two kinds of transmission, orthogonal complementary codes have the ideal auto-correlation and cross-correlation by way of direct-sequence spreading system, so it can solve multipath interference and multi-access interference effectively. While in offset stacked spreading system, orthogonal complementary codes have ideal cross-correlation. Modulating the offset chip time of offset stacked spreading properly can also solve multipath interference effectively. Moreover, GPC code keeps sub-ideal auto-correlation and cross-correlation, and it forsakes its ideal property to exchange for spreading codes with more users. In Chapter 2, we start to introduce complete complementary codes and its property to resist interferences in different transmission. Chapter 3 is the introduction of super complementary codes and its property to resist interferences in different transmission. Chapter 4 is the introduction of GPC code. We explain that GPC code forsakes its ideal property to exchange for spreading codes with more users. Chapter 5 is the introduce multi-rate orthogonal complementary codes and use 2D OVSF to suport different transmission speed.