Human's attitude to nature has been changing through history. This was reflected on architecture, associated with each historical period, connected to availability of appropriate technology, where architecture was to protect man, give him a sense of security, luxury or controlling of nature. However, nature has been considered as a major source of inspiration through analogy of organism, which remained effecting until the industrial revolution and the emergence of other sources of analogies like machines and other. The contemporary period witness an attitude towards returning back to nature through bio-analogies, which appeared in many contemporary architectural trends by the impact of new scientific theories like fractional geometry, chaos theory, self-generation,…etc., associated by the revolution in digital technology and manufacturing. In addition to the emergence of the urgent need to achieve sustainability, which affected strongly in this direction that seeks to improve their aesthetic, functional and structural values. In spite of the multiplicity of these trends, they share the attitude to nature as source of inspiration through bio-analogy. So the problem of search is emerged as "the need to identify levels of bio- analogies in contemporary architecture". And the goal of research is determined as "identifying levels of bio-analogies in contemporary architecture". In light of that, the search classification levels of bio-analogies, and its relation to the characteristics of organisms in each level, and then extract their vocabularies to measure the application in contemporary architectural practice through the projects that are selected as case studies. The research found that they have achieved certain vocabularies and not others.