Economic complexity approach means that in the economy, produced products can be representatives for required knowledge and knowhow. Thus recognizing the level of product complexity will help us to identify the level of knowledge and knowhow embedded in economies. Therefore, in this paper, we tried to introduce economic complexity and its method of calculation to measure the amount of knowledge and knowhow in the economy. For this reason, first, the term of economic complexity was explained and then how economic complexity uses diversity and ubiquity to measure knowledge and knowhow embedded in products and countries were described as well. At the end, we looked at the situation of knowledge and knowhow embedded in Iran based on the economic complexity approach.