Heparan sulfate (HS) has multifaceted biological activities. To date, no libraries of HS oligosaccharides bearing systematically varied sulfation structures are available owing to the challenges in synthesizing a large number of HS oligosaccharides. To overcome the obstacles and expedite the synthesis, a divergent approach was designed, where 64 HS tetrasaccharides covering all possible structures of 2‐O‐, 6‐O‐ and N‐sulfation with the glucosamine‐glucuronic acid‐glucosamine‐iduronic acid backbone were successfully produced from a single strategically protected tetrasaccharide intermediate. This extensive library helped identify the structural requirements for HS sequences to have strong fibroblast growth factor‐2 binding but a weak affinity for platelet factor‐4. Such a strategy to separate out these two interactions could lead to new HS‐based potential therapeutics without the dangerous adverse effect of heparin‐induced thrombocytopenia.