This paper introduces Jade Bird Component Description Language (JBCDL) which is a part of Jade Bird Component Library (JBCL). JBCDL is based on Jade Bird Component Model (JBCOM). JBCOM is a 3C-based hierarchic component model that is composed of specification and implementation layers and with uniformity and self-contained composition. The main purpose of JBCDL is to describe component interface. It mainly applies to component composition under the help of (semi-) automatic tools. JBCDL has the following features: 1) code-wares and design-wares that adopt object-oriented paradigm as the description objects; 2) adopting object-oriented paradigm itself; 3) uniformly describing components of different forms ( such as class, framework, and etc.); 4) integrating well with Jade Bird Component Library.